Chapter ke text par jao
ExplorationCh 5 Mixtures ki Khoj aur unka Separation

Exploring Mixtures and their Separation (Mixtures ki Khoj aur unka Separation): Class 9 Science Chapter 5 Hinglish mein

Exploration · Hinglish notes, simulations aur practice · Official NCERT chapter PDF ↗

Published · Updated

  • 110 min
  • 1 simulation
  • 28 practice questions
  • 31 MCQs

Is chapter mein aap kya seekhenge

  • Particle size, settling, filtering aur light ki madad se mixtures ko homogeneous ya heterogeneous mein, aur solutions, suspensions ya colloids mein classify karo
  • Solution ka concentration mass by mass, mass by volume aur volume by volume percentage mein calculate karo, aur ulta chalkar nikaalo ki kitna solute chahiye
  • Solubility curves padho aur predict karo ki saturated solution thanda hone par kitna solid crystallize hota hai
  • Homogeneous mixture ke parts alag karne ke liye crystallization, distillation ya paper chromatography chuno aur samjhao
  • Heterogeneous mixture ke parts alag karne ke liye separating funnel, sublimation, centrifugation ya coagulation chuno aur samjhao
  • Tyndall effect samjhao aur common colloids aur emulsions ka dispersed phase aur dispersion medium batao
  • Separation methods ko roz ki zindagi se jodo: salt pans, perfume banana, blood banks, water treatment aur waste segregation

NCERT Science Class 9, Chapter 5, pp. 72–93 par based original companion text. Yeh NCERT se juda nahi hai aur NCERT ne ise endorse nahi kiya hai.

Aaj ki teen aam cheezon ko dekho. Tumhari plate ka namak sea water se shuru hua tha. Scooter ka petrol gaadhe, kaale crude oil se shuru hua tha. Health camp ki blood report kuch boond blood se shuru hui thi jo ek chhoti machine mein ghumaya gaya. Har baar kisi ko ek mixture ko alag-alag karna pada, aur har baar unhone woh method chuna jo us mixture ke liye theek tha.

Class 6 mein tumne sorting, sieving, filtering aur evaporation kiya tha. Yeh chapter usse aage jaata hai. Tum naapoge ki ek solution kitna strong hai, aise curves padhoge jo batate hain ki kitna solid dissolve ho sakta hai, aur un methods se miloge jo laboratories, factories aur hospitals use karte hain: crystallization, distillation, chromatography, sublimation, centrifugation aur coagulation. Tum yeh bhi seekhoge ki torch ki beam fog mein kyun dikhti hai lekin saaf paani mein kyun nahi.

5.1 Mixtures ko Classify Kaise Karein?

Paani ke beaker mein copper sulfate ke kuch blue crystals ghol do aur hilao. Liquid har jagah ek jaisa halka blue ho jaata hai: upar, neeche, glass ke paas aur beech mein. Kahin se bhi ek boond lo, usmein copper sulfate ka hissa same hoga. Aisa mixture, jiska composition har jagah same ho, homogeneous mixture (समांगी मिश्रण) kehlata hai.

Har solution homogeneous hota hai, aur waisa hi rehta hai: soda water ki band bottle ya saline ki drip bottle kitni bhi der rakhi rahe, kabhi layers mein alag nahi hoti. Air gases ka homogeneous mixture hai. Stainless-steel ki chammach bhi hai, jo iron hai jismein chromium, nickel aur thoda carbon barabar faile hue hain.

Ab ek chammach mitti paani mein milao. Tum grains ko ghoomte dekh sakte ho, aur kuch hi minutes mein woh neeche baithne lagte hain. Glass ke neeche se li gayi boond mein upar wali boond se kahin zyada mitti hoti hai. Aisa mixture, jiska composition jagah-jagah badalta hai, heterogeneous mixture (विषमांगी मिश्रण) kehlata hai. Paani par tairta tel, peanuts wala poha ka katora aur hawa mein dhuaan bhi heterogeneous hain.

Definition
Homogeneous mixture

Aisa mixture jiska composition har hisse mein same ho, isliye uske components alag se dikhte nahi.

ExamplePaani mein ghuli cheeni; air; brass.

Definition
Heterogeneous mixture

Aisa mixture jiska composition ek hisse se doosre hisse mein alag hota hai.

ExamplePaani mein mitti; tel aur paani; bhel puri ki plate.

Yeh do words sirf pehli sorting hain. Kuch mixtures aankh ko uniform dikhte hain, phir bhi true solution se alag behave karte hain. Agli activity aise teen mixtures ko saath-saath compare karti hai.

2/4Beam A mein invisible hai lekin B aur C mein ek raasta roshan karti hai.

Fig. 5.1Chaar tests teen mixtures ko sort karte hain jo shuru mein kaafi ek jaise dikhte hain.NCERT Fig. 5.3 · p. 73

Teen tumblers saath-saath rakhe hain, jin par A cheeni wala paani, B paani mein aata aur C patla kiya doodh likha hai. Pehle step mein, hilane ke turant baad, A saaf hai, B dhundhla hai aur usmein kann dikhte hain, aur C ek jaisa halka safed hai. Doosre step mein ek patli beam left se har tumbler mein jaati hai; A ke andar beam invisible hai lekin B aur C ke andar ek chamakti band ki tarah dikhti hai. Teesre step mein, rakhe rehne ke baad, B ke kann neeche ek layer mein baith gaye hain jabki A aur C waise hi hain. Aakhri step mein har liquid ko filter paper se daala jaata hai; sirf B paper par residue chhodta hai.

Quick check
3 mein se 1
Saare homogeneous mixtures chuno.
Saare sahi options chuno
Answer dekho
Answer
  • (A) band jar mein air
  • (C) drip bottle ka saline
  • (E) brass ki chaabi
Air, saline aur brass ka composition har jagah same hai. Paani mein mitti aur paani par tel jagah-jagah badalte hain, isliye woh heterogeneous hain.

5.2 Solutions

Nimbu pani ka glass kai parts wala solution hai. Cheeni, namak aur nimbu ka ras solutes hain: woh substances jo dissolve hote hain. Paani solvent hai: woh substance jismein woh dissolve hote hain. Solvent aam taur par woh part hota hai jo zyada maatra mein ho.

Definition
Solution

Ek ya zyada solutes ka solvent mein ghula hua homogeneous mixture.

ExamplePaani (solvent) mein cheeni (solute).

Solutions hamesha paani mein bane liquids nahi hote. Soda water mein ek gas (carbon dioxide) paani mein ghuli hoti hai. Air gas-in-gas solution hai. Brass copper mein zinc ka solid solution hai. Lekin kya ghula hai, yeh jaanna sirf aadhi baat hai. Humein yeh bhi batana hota hai ki kitna.

5.2.1 Solution ka concentration

Kai health workers oral rehydration solution (ORS) ki ghar wali recipe sikhate hain: ek litre saaf paani mein chhe level teaspoon cheeni aur aadha level teaspoon namak. Namak double kar do to yeh drink pehle se kamzor bachche ko nuksaan pahuncha sakti hai. Cheeni aadhi kar do to body paani kam achhe se absorb karti hai. Proportion badlo to tumhare paas bas ek meethi, namkeen drink hai, dawai nahi.

Proportion ORS se kahin aage tak maayne rakhta hai. Water-supply staff germs maarne ke liye bas utna chlorine daalte hain jitna zaroori ho: bahut kam ho to paani unsafe rehta hai, aur bahut zyada ho to usmein smell aati hai aur irritation hota hai. Jaipur ka ek dyer har vat ke liye dye tolta hai, kyunki halke bath se kapda feeka rang leta hai. Nurse injection use karne se pehle us par chhapi strength check karti hai. Har case mein hum solution ke concentration (सांद्रता) ki baat kar rahe hain.

Definition
Concentration

Solution (ya solvent) ki di gayi maatra mein kitna solute hai.

5.2.2 Concentration ko hum kaise express karte hain?

Ghar par labels padho. Namkeen ke packet par uska salt aur fat "per 100 g" likha hota hai. Hand sanitiser par "ethyl alcohol 70 % v/v" likha ho sakta hai. Mouthwash ya eye drops ki bottle bhi apni dawai percentage mein batati hai. Har label ek sawaal ka jawaab deta hai: mixture ki har 100 units mein kitna solute hai? Concentration batane ke aur tareeke bhi hain, jo tum aage ki classes mein seekhoge. Yahan hum teen tarah ke percentage use karte hain, jo Fig. 5.2 mein dikhaye gaye hain.

3/3100 mL solution mein solute ke millilitres.

Fig. 5.2Har percentage solute ko poore solution ki 100 units se compare karta hai, solvent se nahi.NCERT Fig. 5.4 · p. 74

Teen containers ek line mein rakhe hain: kitchen scale par ek beaker, ek measuring flask aur ek measuring cylinder. Pehle step mein scale par rakha beaker highlight hai; scale 100 g solution padhta hai aur ek label kehta hai 12 g salt, jo 12 percent mass by mass hai. Doosre step mein flask highlight hai; woh 100 mL mark tak bhara hai aur ek label kehta hai 0.4 g urea, jo 0.4 percent mass by volume hai. Teesre step mein measuring cylinder highlight hai; woh 100 mL mark tak bhara hai aur ek label kehta hai 70 mL alcohol, jo 70 percent volume by volume hai.

A. Mass by mass percentage (% m/m ya % w/w)

Jab solute aur solution dono ko tolna aasaan ho, to hum masses compare karte hain. Mass by mass percentage har 100 g solution mein solute ke grams ki sankhya hai. Yaad rakho ki solution ka mass solute ka mass plus solvent ka mass hota hai.

mass by mass percentage
% m/m=solute ka masssolution ka mass×100
(5.1)

Percent by mass sirf solutions ke liye nahi hai. NPK fertiliser ka bag, tooth powder ka dibba aur biscuit packet par "per 100 g" nutrition panel, sab ise use karte hain, jabki inmein se koi bhi solution nahi hai.

Example 5.1NCERT Example 5.1 · p. 75

Nimbu achaar ke liye brine

Nimbu ka achaar daalne ke liye ek cook 176 g paani mein 24 g namak gholta hai. Brine ka concentration mass by mass percentage mein kitna hai?

Pehle khud try karo. Phir solution ek-ek step karke kholo.

B. Mass by volume percentage (% m/v ya % w/v)

Pharmacists aur laboratory staff liquid ko shayad hi kabhi tolte hain: use measuring flask mein daalna kahin tez hai. Isliye liquid mein ghule solid ke liye woh aksar mass by volume percentage use karte hain, yaani har 100 mL solution mein solute ke grams. Drips, injections aur kai syrups par yahi label hota hai.

mass by volume percentage
% m/v=solute ka mass (g)solution ka volume (mL)×100
(5.2)
Example 5.2NCERT Example 5.2 · p. 75

Kitchen garden ke liye fertiliser

Meena ek bottle mein paani mein 6 g urea gholti hai aur tab tak paani daalti hai jab tak solution 1.5 L na ho jaaye. Mass by volume percentage mein iska concentration kitna hai?

Pehle khud try karo. Phir solution ek-ek step karke kholo.

C. Volume by volume percentage, yaani % v/v

Agar solute khud ek liquid hai, to dono parts ko millilitres mein naapna sabse aasaan hai. Volume by volume percentage har 100 mL solution mein solute ke millilitres batata hai. Ise sanitisers, mouthwashes aur kuch tonics ke alcohol content par dhoondho.

volume by volume percentage
% v/v=solute ka volumesolution ka volume×100
(5.3)
Example 5.3NCERT Example 5.3 · p. 76

Hand sanitiser

Ek chhoti factory 200 mL hand sanitiser banane ke liye 140 mL ethanol (alcohol) ko paani, thodi glycerine aur ek fragrance ke saath milati hai. Ethanol ka volume by volume percentage nikaalo.

Pehle khud try karo. Phir solution ek-ek step karke kholo.

Dukaanon aur factories mein tumhe aksar % m/m ki jagah % w/w (weight by weight) dikhega. Roz ke use mein yahan weight aur mass ko ek hi cheez maana jaata hai, isliye 5 % w/w label ka matlab bilkul 5 % m/m jaisa hai.

Example

Ulta chalkar: kitni cheeni?

Ek mithai ki dukaan ko 250 g sugar syrup chahiye jo 20 % m/m cheeni ho. Kitni cheeni aur kitna paani tolna chahiye?

Pehle khud try karo. Phir solution ek-ek step karke kholo.

Quick check
3 mein se 1
135 g paani mein 15 g cheeni ghuli hai. Cheeni ka mass by mass percentage kitna hai?
%
Answer dekho

Answer 10 %

Solution ka mass = 15 g + 135 g = 150 g, isliye % m/m = 15 ÷ 150 × 100 = 10 %. 135 g se divide karne par 11.1 % aata hai, jo common galti hai.
Practice · 3 questions

Ruko aur socho (NCERT in-text, p. 76): answers ke saath

  1. NumericalEasyNCERT Pause and Ponder Q1

    Chaat masala ke 400 g jar mein 6 % m/m kaala namak hai. Jar mein kitna kaala namak hai?

    g
    Solution dikhao

    Answer24 g

    Kaala namak = 6 ÷ 100 × 400 g = 24 g.

  2. NumericalEasyNCERT Pause and Ponder Q2

    Mehmaanon ke liye tum jug mein 40 mL rose syrup daalte ho aur thanda paani tab tak milate ho jab tak drink 250 mL na ho jaaye. Drink mein syrup ka volume by volume percentage kitna hai?

    %
    Solution dikhao

    Answer16 % v/v

    % v/v = 40 mL ÷ 250 mL × 100 = 16 %.

  3. Short answerMediumNCERT Pause and Ponder Q3

    Ek kisaan ke paas pure neem oil hai aur use apne vegetable plot ke liye 2 % v/v neem-oil spray ka 5 L chahiye. Batao use yeh kaise taiyaar karna chahiye.

    Solution dikhao

    Answer100 mL neem oil naapo aur tab tak paani daalo jab tak total volume 5 L na ho jaaye.

    5 L = 5000 mL. Zaroori neem oil = 2 ÷ 100 × 5000 mL = 100 mL.

    Use ek container mein 100 mL neem oil naapna chahiye aur phir hilate hue tab tak paani daalna chahiye jab tak total volume 5000 mL na ho jaaye (lagbhag 4900 mL paani). Tel aur paani apne aap nahi milte, isliye liquid soap ki kuch boondein tel ko paani mein phailane mein madad karti hain (dekho Section 5.5 mein emulsions).

5.2.3 Substances ki solubility

Ek glass paani mein cheeni daalte raho, har baar hilate hue. Pehle har chammach gayab ho jaati hai. Jaldi ya der se crystals neeche hi pade rehne lagte hain, chahe kitna bhi hilao. Ab paani us temperature par jitni cheeni rakh sakta hai, utni rakh raha hai. Yeh saturated solution (संतृप्त विलयन) ban gaya hai. Us point se pehle, jab yeh aur le sakta tha, yeh unsaturated tha.

Solute ka woh mass jo 100 g solvent ko bas saturate kar de, us solute ki solubility (विलेयता) kehlata hai. Solubility ki value ke saath hamesha ek temperature chahiye. Cheeni wale paani ke glass ko garam karo to neeche pade crystals ghul jaate hain, kyunki zyaadatar solids ki solubility temperature badhne par badhti hai. Isiliye garam chai mein cheeni jaldi gayab ho jaati hai lekin iced tea mein der tak padi rehti hai.

Definition
Solubility

Kisi diye gaye temperature par 100 g solvent mein ghulne wala solute ka sabse zyada mass.

Example20 °C par 100 g paani mein lagbhag 36 g common salt.

Definition
Saturated solution

Aisa solution jismein us temperature par jitna ho sake utna solute ghula ho; extra solute bina ghule reh jaata hai.

Gases ulta behave karti hain. Garam soda ki bottle kholte hi jhaag ke saath bahar nikalti hai, kyunki garam paani kam carbon dioxide rakhta hai. Garmi mein talaabon mein kam dissolved oxygen hoti hai, aur machhliyan surface par muh kholkar saans leti dikhti hain. To: solids aam taur par garam paani mein zyada ghulte hain, gases kam ghulti hain. Solubility ke fark mixtures ko alag karne ke main tools mein se ek hain, jaisa tum aage dekhoge.

2/340 °C par 100 g paani 80 g P ghol leta hai lekin Q sirf 54 g.

Fig. 5.3Do kalpanik compounds: P ki solubility temperature ke saath tezi se badhti hai; Q ki mushkil se badalti hai.NCERT Fig. 5.6 · p. 77

Ek graph jismein across 0 se 80 degrees Celsius tak temperature hai aur side mein upar 0 se 200 grams per 100 grams paani tak solubility. Pehle step mein do curves bane hain: compound P 0 degrees par 15 grams se 80 degrees par 190 grams tak tezi se badhta hai, jabki compound Q lagbhag flat hai, 46 se 62 grams tak badhta hai. Doosre step mein 40 degrees par dashed guide lines dikhati hain ki P 80 grams par aur Q 54 grams par hai. Teesre step mein P curve par ek neeche ki taraf arrow 60 degrees par 130 grams se 40 degrees par 80 grams tak jaata hai, jis par 50 grams crystals likha hai.

Quick check
3 mein se 1
Fig. 5.3 se: 20 °C par P ki solubility 60 °C par uski solubility hai, aur 20 °C par Q ki solubility 60 °C par uski solubility hai.
Answer dekho

Answer (1) less than, (2) similar to

P 40 g se 130 g tak jaata hai, isliye 20 °C par yeh kahin kam hai. Q 50 g se 58 g tak jaata hai, isliye dono values lagbhag same hain.

5.3 Homogeneous Mixtures ko Alag Karne ke Methods

Homogeneous mixture mein parts bilkul single particles tak mile hote hain. Koi sieve, filter paper ya magnet unhe alag nahi kar sakta. Unhe alag karne ke liye humein woh property use karni padti hai jismein parts alag hon: temperature ke saath solubility kaise badalti hai, har part kitni aasaani se boil hota hai, ya har part paper se kitni mazbooti se chipakta hai.

5.3.1 Crystallization

Fig. 5.3 mein compound P par wapas jao. 60 °C par 100 g paani 130 g P rakh sakta hai. Maan lo hum bilkul aisa saturated solution banate hain aur use 40 °C tak thanda hone dete hain. Ab paani sirf 80 g rakh sakta hai. Extra 50 g ke liye koi jagah nahi, isliye woh solid ban kar solution se bahar aa jaata hai. Agar thanda hona dheere ho, to yeh solid saaf, chamakte crystals ki tarah dikhta hai.

Crystal mein particles ek saaf arrangement mein baithe hote hain jo baar-baar repeat hota hai, jaise achhi bani deewar mein eentein. Yeh andar ka order bahar flat faces aur seedhe edges ke roop mein dikhta hai. Tumne kai dekhe hain: dhaage par latke mishri ke tukde, shave ke baad use hone wale alum (fitkari) ke tukde, snowflakes ke chhe bhujaon wale shapes, aur granite kitchen slab mein chamakte grains.

Laboratory mein saturated solution se crystals ugaana crystallization (क्रिस्टलीकरण) kehlata hai. Yeh kisi solid ko purify karne ka standard tareeka hai. Jab koi naya compound banta hai, to usmein aam taur par thodi maatra mein unwanted substances hote hain. Impure solid ko garam solvent mein gholo aur thanda hone do: main substance zyada maatra mein hai, isliye woh saturate hokar crystallize hota hai. Impurities bahut thodi maatra mein hain, isliye woh kabhi saturation tak nahi pahunchti aur ghuli rehti hain. Yeh method isliye kaam karta hai kyunki solubility temperature par depend karti hai.

Definition
Crystallization

Kisi pure solid ko uske saturated solution se crystals ke roop mein paane ka process, solution ko thanda karke ya solvent ko dheere-dheere evaporate hone dekar.

ExampleAlum ya copper sulfate ko purify karna; sugar syrup se mishri banana.

3/4Crystal ek regular grid mein badhta rehta hai; impurities solution mein hi rehti hain.

Fig. 5.4Thanda karne se main solute crystal ban kar bahar aata hai; impurity ke thode particles liquid mein hi reh jaate hain.NCERT Fig. 5.8 · p. 78

Left mein thermometer ke saath solution ka beaker hai; right mein ek magnifying circle andar ke particles dikhata hai. Pehle step mein solution 70 degrees par hai: gol solute particles aur kuch triangular impurity particles aazaadi se ghoom rahe hain. Doosre step mein solution 45 degrees tak thanda ho gaya hai; solute particles circle ke neeche ek chhote square block mein line lagane lagte hain. Teesre step mein, 25 degrees par, block badhkar ek bada regular grid ban gaya hai jabki triangular impurity particles abhi bhi liquid mein bikhre hain. Aakhri step mein crystals ko filter paper par utha liya jaata hai aur impurities wala liquid neeche beh jaata hai.

Solution ko boil karke poora sukha kyun na dein? Iske do kaaran hain. Pehla, kuch solids zyada garam karne par badal jaate hain ya toot jaate hain: sugar syrup ko poora sukhane tak boil karo to woh brown hokar jal jaata hai. Doosra, jab solvent ki har boond uda di jaati hai, to soluble impurities bhi solid par sookh jaati hain. Crystallization mein impurities bache hue liquid mein reh jaati hain, isliye crystals kahin zyada pure hote hain.

Example

Thanda karne par kitne crystals?

Potassium nitrate ki solubility 60 °C par lagbhag 110 g per 100 g paani aur 20 °C par lagbhag 32 g per 100 g paani hai. 60 °C par 50 g paani se bana saturated solution 20 °C tak thanda kiya jaata hai. Kitna mass potassium nitrate crystallize hota hai?

Pehle khud try karo. Phir solution ek-ek step karke kholo.

InteractiveSolubility aur crystal lab

0 se 100 degrees Celsius tak ka solubility graph jismein potassium nitrate, cheeni aur common salt ke curves hain; chune gaye solid ka curve highlight hai. Sliders paani ka mass aur ek garam aur ek thanda temperature set karte hain. Curve par do markers aur ek neeche ki taraf arrow har temperature par solubility dikhate hain. Readouts batate hain ki garam hone par kitna mass paani ko saturate karta hai, thanda hone par kitna ghula reh sakta hai, aur kitne mass ke crystals bante hain, saath mein ek beaker drawing jiski crystal layer usi hisaab se badhti hai. Ek note samjhata hai ki kab thanda karna crystallize karne ka kharab tareeka hai, jaise common salt ke liye.

Fig. 5.5Ek solid chuno, paani ki maatra aur do temperatures set karo, aur dekho ki saturated solution thanda hone par kitna crystallize hota hai.
Practice · 2 questions

Ruko aur socho (NCERT in-text, p. 79): answers ke saath

  1. Short answerMediumNCERT Pause and Ponder Q4

    Fig. 5.3 use karo. P aur Q ke saturated solutions, har ek 80 °C par 100 g paani se banakar, 60 °C tak thande kiye jaate hain. Kaunsa solution zyada solid chhodta hai, aur kitna zyada?

    Solution dikhao

    AnswerP 60 g chhodta hai; Q sirf lagbhag 4 g, isliye P lagbhag 56 g zyada chhodta hai.

    P: 190 g − 130 g = 60 g bahar aata hai. Q: 62 g − 58 g = 4 g bahar aata hai. P ka curve kahin zyada steep hai, isliye thanda karne se uska kahin zyada hissa bahar nikalta hai: Q se lagbhag 56 g zyada.

  2. Short answerMediumNCERT Pause and Ponder Q5

    Same salt solution ki do plates sookhne ke liye chhodi jaati hain: ek tez dhoop mein jis par pankha chal raha hai, doosri chhaaon wali shelf par. Dono plates ke salt crystals mein kya fark hoga? Samjhao.

    Solution dikhao

    AnswerChhaaon wali plate kam, bade aur achhi shape ke crystals deti hai; dhoop aur hawa wali plate bahut saare chhote crystals deti hai.

    Tez evaporation se solution har jagah jaldi saturated ho jaata hai, isliye ek saath hazaaron crystals shuru ho jaate hain aur kisi ko bada hone ka time nahi milta. Chhaaon wali shelf par dheere evaporation se kuch crystals paani jaate-jaate badhte rehte hain, isliye woh bade aur achhi shape ke bante hain.

3/4Brine saturated hai, isliye namak pan ke tal par crystallize hota hai.

Fig. 5.6Solar salt: evaporation brine ko saturated banata hai, aur pan ke tal par crystals bante hain.NCERT Fig. 5.9 · p. 79

Left mein samundar aur right mein dhoop ke neeche uthle salt pans ki ek line ka side view. Pehle step mein sea water ek chhote gate se pehle pan mein behta hai. Doosre step mein sooraj aur hawa paani ko evaporate karte hain, jise upar uthte wavy arrows dikhate hain, aur pans mein paani ka level gir jaata hai. Teesre step mein brine saturated hai aur pan ke tal par crystals ki ek safed layer banti hai. Aakhri step mein ek worker ki rake ne crystals ko pan ke paas safed dheron mein kheench liya hai taaki paani nikle aur woh sookhein.

SimulationEvaporation ko kya tez karta hai?

Paani ke particles ka ek khula container, saath mein thermometer aur evaporation counter. Controls temperature ko 0 se 90 degrees tak, upar se behti hawa ki strength, aur surface small hai ya large, yeh badalte hain. Surface ke paas tez particles vapour ban kar nikal jaate hain, aur counter dikhata hai ki kitne nikal chuke hain.

Fig. 5.7Play dabao. Temperature, hawa aur surface area badlo, aur khule container se nikalte particles ka count dekho.
Try karo
  • Temperature 30 °C par rakho. Surface area small se large karne ke baad count compare karo. Salt pans itne chaude aur uthle kyun hote hain?
  • Hawa tez karo. Nikalte particles ko kya hota hai, aur namak banane wale hawadaar, sookha mausam kyun pasand karte hain?
Quick check
3 mein se 1
Crystallization ke steps ko sahi order mein lagao.
  1. Crystals ko filter karke nikaalo
  2. Garam rehte hue filter karo
  3. Dheere-dheere thanda hone do
  4. Garam saturated solution banao
Answer dekho
Answer
  1. Garam saturated solution banao
  2. Garam rehte hue filter karo
  3. Dheere-dheere thanda hone do
  4. Crystals ko filter karke nikaalo
Garam hone par saturate karo, insoluble gandagi filter karo, crystals ugaane ke liye dheere thanda karo, phir filter karke unhe ikattha karo.

5.3.2 Distillation

Jab namak wala paani plate mein sookhta hai, to humein namak milta hai lekin paani hawa mein kho jaata hai. Kabhi-kabhi liquid hi woh part hota hai jo humein chahiye. Samundar mein door ek ship ko sea water se peene ka paani chahiye. Laboratory ko ek mehenga solvent wapas chahiye ho sakta hai. Aur jab do liquids poori tarah mil jaate hain, jaise alcohol aur paani, to sirf evaporation bekaar hai: dono liquids bas hawa mein nikal jaate hain.

Iska jawaab hai liquid ko boil karke udana aur phir use wapas pakadna. Distillation (आसवन) teen stages mein kaam karta hai: boil, cool, collect. Mixture ko garam karo, aur jis liquid ka boiling point kam hai woh pehle vapour ban kar nikalta hai. Us vapour ko ek condenser se guzaaro, jo thande behte paani ke jacket ke andar ek glass tube hai. Thanda hokar vapour phir se liquid ban jaata hai aur distillate ke roop mein tapak kar nikalta hai. Jo kabhi boil nahi hua, jaise ghula namak ya zyada boiling point wala liquid, woh garam flask se kabhi nahi nikalta.

Definition
Distillation

Kisi mixture se ek liquid ko boil karke aur uske vapour ko alag bartan mein condense karke alag karna.

ExampleSea water se pure paani paana; paani se methanol alag karna.

3/4Condenser ke chaaron taraf ka thanda paani vapour ko wapas liquid methanol bana deta hai.

Fig. 5.8Thermometer us liquid ke boiling point ke paas rehta hai jo distill hokar aage jaa raha hai.NCERT Fig. 5.12 · p. 80

Burner ke upar wire gauze par ek distillation flask, jiske side arm par thermometer hai; ek tircha condenser jismein thanda paani neeche wale sire se andar aata hai aur upar wale sire se nikalta hai; aur neeche right mein ek receiving flask. Pehle step mein flask mein methanol aur paani ka thanda mixture hai. Doosre step mein burner jalaya jaata hai, mixture boil hota hai aur vapour thermometer ke paas se upar uthta hai, jo 65 degrees padhta hai. Teesre step mein vapour condenser ke andar condense hota hai aur liquid methanol receiving flask mein tapakta hai. Aakhri step mein methanol khatam ho gaya hai, thermometer 100 degrees tak chadhta hai aur flask mein bacha liquid paani hai.

Fig. 5.8 mein thermometer dekho. Uska bulb side arm par hai, isliye woh flask se nikalte vapour ka temperature naapta hai. Jab tak methanol distill ho raha hai, reading 65 °C ke paas rehti hai. Jab methanol khatam ho jaata hai, reading 100 °C ki taraf chadhti hai, jo humein batati hai ki ruk jao ya collecting flask badal do. Yeh bhi dhyaan do ki thanda paani condenser mein uske neeche wale sire se aata hai aur upar wale sire se nikalta hai, taaki jacket poori tarah thande paani se bhara rahe.

Simple distillation do liquids ko achhe se tabhi alag karta hai jab unke boiling points mein lagbhag 25 °C ya usse zyada ka fark ho, jaise methanol (65 °C) aur paani (100 °C). Agar fark kam ho, to dono liquids badi maatra mein saath boil hokar nikalte hain, aur distillate abhi bhi mixture hota hai. Yeh us liquid ke liye bhi kaam karta hai jismein solid ghula ho: sea water ko distill karo to pure paani tapak kar nikalta hai jabki namak flask mein reh jaata hai.

Quick check
3 mein se 1
Poori tarah milne wale liquids ki kaunsi pair ko simple distillation se achhe se alag kiya ja sakta hai?
Answer dekho

Answer (C) Acetone (56 °C) aur paani (100 °C)

Acetone aur paani mein 44 °C ka fark hai, isliye acetone lagbhag akela boil hokar nikalta hai. Baaki pairs mein 22 °C aur 2 °C ka fark hai, isliye unhe fractional distillation chahiye.

5.3.3 Paper Chromatography

Kya kabhi green sketch pen se likhe homework par paani gira hai? Ink geele page par phail jaati hai, aur dhabbe ka kinaara green ki jagah yellow ya blue dikh sakta hai. Woh "green" asal mein do dyes tha. Paani ne ek dye ko doosre se zyada door kheencha, aur mixture paper par alag hone laga. Yahi accident paper chromatography ke peeche ka idea hai.

3/4Dono dyes alag speeds se chalte hain aur do bands banate hain.

Fig. 5.9Is run mein yellow dye blue se zyada door jaata hai, isliye green dot do bands mein alag hota hai.NCERT Fig. 5.15 · p. 82

Pencil par clip ki gayi ek paper strip ek glass tumbler mein latki hai jismein paani ki patli layer hai. Pehle step mein ek green dot paani ki surface ke thoda upar pencil line par hai. Doosre step mein paper ka geela hissa aadhe tak chadh gaya hai aur dot upar ki taraf khinchne laga hai. Teesre step mein water front top ke paas hai aur dot upar ek yellow band aur neeche ek blue band mein toot gaya hai. Aakhri step mein sookhi strip akeli dikhayi gayi hai, jis par start line, dono rangeen bands aur solvent front mark kiye gaye hain.

Mixture ke ghule parts ko alag karne ka yeh method paper chromatography (क्रोमैटोग्राफी) hai. Yeh har substance par lagne wale do khinchaav par depend karta hai: chalta solvent use aage le jaata hai, aur paper use peeche rokta hai. Kyunki har substance alag respond karta hai, parts alag heights par pahunchte hain. Ismein bas thoda sa sample chahiye, isliye yeh rangon ke liye perfect hai: food colour mein kaunse dyes hain yeh check karna, patti ke green aur yellow pigments alag karna, ya nakli note ki ink ko kisi suspect ke pen ki ink se compare karna.

Definition
Paper chromatography

Mixture ke ghule parts ko alag karne ka method, jismein solvent unhe paper ki strip par alag speeds se upar le jaata hai.

Paani hamesha sahi solvent nahi hota. Permanent marker ki ink paani mein bilkul nahi ghulti, isliye uska dot line par hi rehta. Aisi inks aur patti ke pigments ke liye spirit (alcohol) ya acetone chahiye, kabhi-kabhi dono mila kar.

True ya false? (NCERT Pause and Ponder 6)
4 mein se 1
Namak wale paani se namak aur paani dono wapas paane ke liye distillation kaam karta hai lekin khuli plate mein evaporation nahi.
Answer dekho

Answer Sahi

Evaporation water vapour ko nikal jaane deta hai. Distillation use condense karta hai, isliye paani tumhare paas rehta hai aur namak flask mein bachta hai.

5.4 Heterogeneous Mixtures ke Components ko Kaise Alag Karein?

Heterogeneous mixture mein parts alag tukdon, boondon ya layers ki tarah rehte hain, chahe woh dikhne ke liye bahut chhote hon. Isse principle mein separation aasaan ho jaata hai: humein bas ek property chahiye jismein tukde alag hon, jaise density, size, magnetism ya woh kitni aasaani se vapour bante hain.

5.4.1 Do immiscible liquids ka separation

Ek glass paani mein ek chammach cooking oil daalo aur zor se hilao. Ek pal ke liye tel boondon mein toot jaata hai. Ek minute ke andar boondein upar uthkar ek layer mein jud jaati hain. Jo liquids is tarah nahi milte, woh immiscible (अमिश्रणीय) kehlate hain. Kerosene aur paani, aur petrol aur paani, aur bhi aisi pairs hain. Inke mixtures heterogeneous hain: tum dekh sakte ho ki ek liquid kahan khatam hota hai aur doosra kahan shuru.

Layers density ke order mein banti hain. Zyaadatar tel paani se kam dense hote hain (har millilitre ke liye lagbhag 0.9 g, jabki paani ke liye 1.0 g), isliye tel upar tairta hai. Layers alag karne ke liye hum separating funnel use karte hain: naashpati ke shape ka glass bartan jiske upar stopper aur neeche ek tap hota hai, jise stopcock kehte hain. Hum neeche wale, zyada dense liquid ko tap se bahar behne dete hain aur upar wale ko andar hi rakhte hain.

Definition
Immiscible liquids

Aise liquids jo ek doosre ke saath nahi milte aur rakhe rehne par alag layers bana lete hain.

ExampleTel aur paani; kerosene aur paani.

2/4Kam dense tel upar uthta hai; paani neeche baithta hai.

Fig. 5.10Zyada dense liquid tap ke paas hota hai, isliye woh funnel se pehle nikalta hai.NCERT Fig. 5.16 · p. 83

Ek beaker ke upar stand par clamp kiya hua separating funnel. Pehle step mein, hilane ke turant baad, funnel mein paani mein tel ki boondon ka dhundhla mixture hai. Doosre step mein liquids do layers mein baith gaye hain, upar tel aur neeche rangeen paani. Teesre step mein stopper nikla hai aur stopcock khula hai; paani ki layer neeche beaker mein behti hai aur funnel mein uska level girta hai. Aakhri step mein stopcock band hai, funnel mein sirf tel bacha hai aur beaker mein paani hai.

Aur un mixtures ka kya jinmein gas ho? Leak hoti cooking gas ki smell minutes mein kitchen ke har kone tak pahunch jaati hai, kyunki gas particles tezi se bhaagte hain aur doosri gases ke beech barabar phail jaate hain. Isliye air aur sirf gas wale doosre mixtures homogeneous hain. Lekin gas mein solid kann ya liquid boondein daalo, to result heterogeneous hota hai: puraane diesel truck ka kaala dhuaan, perfume atomiser ki spray ya May mein Rajasthan par chalne wale dust storms.

Solids ke saath mile solids, jaise chawal ke saath chhote kankad ya ret ke saath iron filings, aam taur par apne alag daane banaye rakhte hain. Unhe alag karne ke liye kuch aisa dhoondho jo ek solid karta hai aur doosra nahi: iron magnet se khinchta hai, bhoosa hawa mein ud jaata hai, chhote daane sieve se gir jaate hain. Kuch solids ke paas ek aur trick hai: woh seedhe vapour ban jaate hain.

Quick check
2 mein se 1
Kerosene (density lagbhag 0.8 g/mL) aur paani ko separating funnel mein hilaya jaata hai. Stopcock se tum pehle kaunsa liquid collect karoge?
Answer dekho

Answer (A) Paani, kyunki woh neeche wali layer banata hai

Paani zyada dense hai, isliye woh stopcock ke paas neeche baithta hai aur pehle nikalta hai. Kerosene aakhir tak upar rehta hai.

5.4.2 Sublimation

Almari mein rakhi mothballs (naphthalene balls) mahine dar mahine chhoti hoti jaati hain, phir bhi kabhi paani jaisa kuch nahi chhodti. Puja ki thali par rakhi camphor ki goliyaan bhi dheere-dheere gayab ho jaati hain. Aise solids liquid stage ko poori tarah chhod kar seedhe solid se gas ban jaate hain: yeh sublimation (ऊर्ध्वपातन) hai. Us gas ko thandi surface par thanda karo to wapas aate hue bhi woh liquid stage chhod kar seedhe solid ban sakti hai; ise deposition kehte hain.

3/3Vapour thande glass par wapas solid ban jaata hai: deposition.

Fig. 5.11Camphor garam karne par sublime hota hai aur thande funnel par jam jaata hai; namak dish mein rehta hai.NCERT Fig. 5.17 · p. 84

Flame ke upar tripod aur wire gauze par rakhi china dish, jo ek ulte glass funnel se dhaki hai jiske stem mein cotton plug hai. Pehle step mein dish mein safed camphor aur grey namak ke daanon ka mixture hai aur flame band hai. Doosre step mein flame jalti hai aur dish se camphor vapour ki patli lakeerein upar uthti hain; koi liquid nahi hai. Aakhri step mein solid camphor ke safed flakes funnel ke andar chipke hain, jabki dish mein sirf namak bacha hai.

Definition
Sublimation

Garam karne par kisi solid ka liquid state se guzre bina seedhe vapour mein badalna.

ExampleCamphor, naphthalene, iodine aur dry ice.

Solid carbon dioxide, jise dry ice kehte hain, bhi sublime hota hai. Yeh lagbhag −78 °C thanda hota hai aur koi geela kachra nahi chhodta, isliye transport ke dauraan frozen foods aur kuch vaccines ko thanda rakhta hai, aur stage par "fog" banata hai. Jab bhi mixture mein ek solid sublime hota hai aur doosra nahi, sublimation unhe alag kar sakta hai.

Metals ko milana: alloys

Metal workers bahut pehle se ek trick use karte aaye hain. Do metals jo solid tukdon ki tarah kabhi nahi milte, dono pighalne par poori tarah mil jaate hain, jaise cheeni paani mein gayab ho jaati hai. Is blend ko saanche mein daalo to woh sakht hokar ek uniform metal ban jaata hai. Metals ka aisa uniform blend, kabhi-kabhi carbon jaise non-metal ke saath, alloy kehlata hai.

Pure copper naram hota hai aur pure iron mein jang lagta hai; blend karne se aisi kamzoriyaan door hoti hain. Brass, jo taps, chaabiyon aur musical instruments mein use hota hai, zyaadatar copper hai jismein kuch zinc hai. Bronze, jo ghantiyon aur mashhoor Chola Nataraja statues mein use hota hai, copper hai jismein kuch tin hai; kansa (bell metal) ki thali tin se bharpoor bronze hai. Kitchen ka stainless steel iron hai jismein lagbhag 18 % chromium, lagbhag 8 % nickel aur thoda sa carbon hai. Filtration, distillation ya sublimation jaise physical methods alloy ke metals ko alag nahi kar sakte.

Quick check
2 mein se 1
In mein se kaunse solids halka garam karne par sublime hote hain? Jo bhi hon, saare chuno.
Saare sahi options chuno
Answer dekho
Answer
  • (A) camphor
  • (C) naphthalene
  • (D) dry ice (yaani solid carbon dioxide)
Camphor, naphthalene aur dry ice seedhe vapour ban jaate hain. Namak sirf lagbhag 800 °C par pighalta hai, aur cheeni pighal kar phir jal jaati hai, isliye dono mein se koi sublime nahi hota.
Practice · 2 questions

Ruko aur socho (NCERT in-text, p. 84): answers ke saath

  1. Short answerEasyNCERT Pause and Ponder Q7

    Samjhao ki ek hi funnel mein daale gaye kerosene aur paani milne ki jagah do layers kyun ban jaate hain.

    Solution dikhao

    AnswerWoh immiscible hain, aur kerosene paani se kam dense hai, isliye woh upar baithta hai.

    Kerosene aur paani immiscible hain: unke particles ek doosre ke beech nahi phailte. Kyunki woh alag rehte hain, gravity unhe density ke hisaab se sort karti hai. Paani zyada dense hai aur neeche doob jaata hai; kerosene kam dense hai aur uske upar tairta hai, upar wali layer banata hai.

  2. Short answerMediumNCERT Pause and Ponder Q8

    Kya naphthalene ball ka chhota hona aur geele farsh ka sookhna ek hi change hai? Kaaran do.

    Solution dikhao

    AnswerNahi. Naphthalene sublime hota hai (solid se vapour), jabki paani evaporate hota hai (liquid se vapour).

    Dono changes vapour par khatam hote hain aur dono boiling point se neeche hote hain. Lekin naphthalene solid ke roop mein shuru hota hai aur liquid state chhod deta hai: yeh sublimation hai. Farsh ka paani liquid ke roop mein shuru hota hai: yeh evaporation hai.

5.4.3 Suspensions

Antacid ya calamine lotion ki bottle ka label padho: "Shake well before use." Dawai ek powder hai jo ghulta nahi. Hilane se woh liquid mein phail jaata hai, lekin dheere-dheere phir neeche baith jaata hai. Aisa heterogeneous mixture, jismein bina ghule solid particles kuch der ke liye liquid mein phaile rehte hain, suspension (निलंबन) kehlata hai.

Ghule particles ke mukable yeh grains giants hain: tum inhe aankhon se ya hand lens se dekh sakte ho. Inka size do aur clues samjhata hai. Mixture rakhe rehne par yeh neeche baith jaate hain, aur filter paper inhe pakad leta hai. Paani mein mitti, paani mein chalk powder aur Activity 5.1 ka aata suspensions hain.

Definition
Suspension

Aisa heterogeneous mixture jiske solid particles ghulte nahi, dikhte hain, aur mixture rakhe rehne par neeche baith jaate hain.

ExampleMuddy paani; paani mein chalk powder.

Toofan ke baad talaab ke paani ki ek balti problem dikhati hai. Raat bhar mein ret aur kankad neeche baith jaate hain (sedimentation), aur upar ka paani dheere se nikaala ja sakta hai (decantation). Muslin ka kapda thodi aur gandagi pakad leta hai. Phir bhi paani mein din bhar tak ek halki brown dhundh latki reh sakti hai: clay ke sabse baareek particles kapde ke gaps se nikal jaate hain aur itne halke hain ki jaldi neeche nahi baithte. Aise ziddi particles ke liye do methods hain: unhe ghuma kar nikaalna, ya unhe ek saath jod kar gucchhe banana.

A. Centrifugation

Tez ghoomte merry-go-round par baitho to tumhe bahar ki taraf dhakka lagta mehsoos hota hai. Washing machine ka spin cycle yahi effect use karta hai: kapde drum se chipak jaate hain jabki paani uske chhedon se bahar phenk diya jaata hai. Laboratory ke centrifuge mein mixture ki tubes ek rotor se latakti hain jo ek minute mein hazaaron baar ghoomta hai. Speed badhne par har tube bahar ki taraf jhool kar lagbhag flat ho jaati hai. Ab tube ki har cheez centre se door phenki jaati hai, aur zyada dense particles jeet jaate hain: woh centre se sabse door wale sire mein, yaani tube ke neeche, bhar jaate hain. Halka liquid khule sire ke paas reh jaata hai. Is tarah mixture ko alag karna centrifugation kehlata hai.

3/4Particles neeche bhare hain; upar saaf liquid hai.

Fig. 5.12Ghumaana minutes mein woh kar deta hai jo neeche baithne mein ghante ya din lagte.NCERT Fig. 5.19 · p. 85

Centrifuge ka side view: ek khada spindle jiske do arms hain, har arm par ek hinged tube. Pehle step mein machine ruki hai, tubes seedhi neeche latki hain aur unke andar sab kuch ek jaisa dhundhla hai. Doosre step mein arms ghoomte hain; tubes bahar jhool kar lagbhag flat ho gayi hain, aur arrows dikhate hain ki particles tubes ke door wale siron ki taraf bahar ja rahe hain. Teesre step mein machine ruk gayi hai, tubes phir neeche latki hain, aur har tube ke neeche ek bhari hui layer hai jiske upar saaf liquid hai. Aakhri step mein blood ki ek tube badi karke dikhayi gayi hai: upar halka peela plasma, white cells aur platelets ki ek patli safed si layer, aur neeche bhare hue red cells.

Dairies cream separators naam ke centrifuges use karti hain: halki cream ghoomte bowl ke centre ke paas jama hoti hai aur nikaal li jaati hai. Pathology laboratories blood samples ko ghumaati hain taaki halka peela plasma cells se alag ho jaaye, aur factories liquids se solids nikaalne ke liye bahut bade centrifuges use karti hain.

B. Coagulation

Kai Indian gharon mein dhundhle paani ki balti mein alum (fitkari) ka tukda ghumaya jaata hai aur balti ko rakh diya jaata hai. Kuch ghanton baad gandagi neeche hoti hai aur upar ka paani saaf. Alum baareek particles ko ek doosre se chipka kar kaam karta hai. Saikdon particles judkar flocs naam ke fluffy gucchhe banate hain, jo doobne layak bhaari hote hain. Unke baith jaane ke baad saaf paani nikaal liya jaata hai ya filter kiya jaata hai. Koi bhi process jo chhote suspended particles ko gucchhon mein ikattha kare, coagulation (स्कंदन) hai; iske liye daala gaya substance, jaise alum, coagulant kehlata hai.

3/4Bhaari gucchhe doob jaate hain: sedimentation.

Fig. 5.13Alum baareek particles ke gucchhe banata hai; gucchhe neeche baithte hain aur saaf paani decant kiya jaata hai.NCERT Fig. 5.21 · p. 86

Dhundhle paani ka ek glass jiske paas ek magnifying circle hai. Pehle step mein glass ek jaisa dhundhla hai aur circle bahut saare chhote alag-alag particles dikhata hai. Doosre step mein pisa alum daala jaata hai; circle dikhata hai ki chhote particles chipak kar kuch bade gucchhe ban rahe hain. Teesre step mein gucchhe glass ke neeche ek layer mein doob gaye hain aur upar ka paani saaf hai. Aakhri step mein saaf paani ko doosre glass mein nikaala ja raha hai, aur sediment peeche reh jaata hai.

Definition
Coagulation

Bahut chhote suspended particles ko gucchhon mein jodna, aam taur par coagulant daal kar, taaki woh neeche baith jaayein.

ExampleAlum se muddy paani saaf hona; citric acid se garam doodh phat kar chhena banna.

Water-treatment plants paani ko filter aur disinfect karne se pehle yahi trick bahut bade paimaane par use karte hain. Coagulation mithai ki dukaanon mein bhi hota hai. Rasgulle ke liye chhena banane ko halwai ubalte doodh mein chutki bhar citric acid (nimbu sat), ya pichhle batch ka khatta whey daalta hai. Doodh ke proteins naram safed curds ke gucchhe ban jaate hain, jinhe muslin se chhaana jaata hai. Aur jab tumhari ungli kat jaati hai, to cut ke paas ka blood coagulate hota hai, yaani jam jaata hai, aur use seal kar deta hai.

Quick check
3 mein se 1
Har mixture ko use alag karne ke sabse achhe tareeke se match karo.

Left mein koi item tap karo, phir right mein uska match.

Answer dekho
Answer
  • talaab ke paani mein baareek clay : alum daalo, phir decant karo
  • blood cells se plasma : centrifugation
  • paani se ret : filtration
  • namak se camphor : sublimation
Clay filter karne ke liye bahut baareek hai, isliye alum uske gucchhe banata hai. Blood cells ghuma kar alag kiye jaate hain. Ret ke daane itne bade hain ki filter paper unhe rok le. Camphor sublime hota hai aur namak nahi.

5.4.4 Colloids

Ab Activity 5.1 ke patle doodh ko phir se dekho. Woh uniform dikhta tha, kabhi neeche nahi baitha, aur filter paper se seedha guzar gaya, bilkul solution ki tarah. Phir bhi light beam uske andar dikhi, bilkul suspension ki tarah. Doodh dono mein se kuch nahi hai. Yeh ek teesre group, colloids (कोलॉइड), ka hai. Whipped cream, mayonnaise, jelly, shaving foam, fog aur, jaise yeh book ise maanti hai, blood bhi colloids hain.

Solutions, colloids aur suspensions ko asal mein unmein phaile particles ka size sort karta hai (Fig. 5.14). Size nanometres (nm) mein naapa jaata hai; ek nanometre ek millimetre ka millionth hissa hai. Solution mein ghule particles lagbhag 1 nm se chhote hote hain. Colloid mein woh lagbhag 1 se 1000 nm ke hote hain. Suspension mein woh lagbhag 1000 nm se bade hote hain. Comparison ke liye, insaan ka ek baal lagbhag 70 000 nm mota hota hai.

1/41 nm se neeche: solution. 1 se 1000 nm: colloid. 1000 nm se upar: suspension.

Fig. 5.14Har mark pichhle se das guna hai. Particle size tay karta hai ki mixture kaise behave karega.NCERT Fig. 5.23 · p. 87

Ek horizontal size scale jis par 0.1, 1, 10, 100, 1000, 10 000 aur 100 000 nanometres par marks hain, har mark pichhle se das guna. Pehle step mein teen rangeen bands bane hain: 1 nanometre se neeche solution, 1 se 1000 nanometres tak colloid aur 1000 nanometres se upar suspension. Doosre step mein solution band ek example, cheeni ke particle, ke saath highlight hai, aur ek note kehta hai ki yeh filter paper se guzarta hai aur kabhi neeche nahi baithta. Teesre step mein colloid band doodh ke ek chhote protein kann ke saath highlight hai: yeh filter paper se guzarta hai aur neeche nahi baithta, lekin light scatter karta hai. Aakhri step mein suspension band aate ke daane ke saath highlight hai, aur ek marker dikhata hai ki filter paper ka chhed lagbhag 10 000 nanometres chauda hai: daana ruk jaata hai aur neeche baithta hai.

Definition
Colloid

Aisa heterogeneous mixture jiske particles, lagbhag 1 se 1000 nm ke, barabar phaile rehte hain, filter paper se guzar jaate hain aur light scatter karte hain.

ExampleDoodh, fog, ice cream, tomato ketchup.

Colloid ko ek hafte chhod do, phir bhi woh neeche nahi baithega. Uske particles itne chhote hain ki har taraf se lagatar takrate water molecules unhe chalte aur phaile rakhte hain, bilkul solution ki tarah. Sirf ek zordaar push, jaise centrifuge ya coagulant, unhe bahar laata hai.Blood ek special case hai. Uske proteins plasma mein colloid banate hain, lekin uske red cells lagbhag 7000 nm ke hote hain, suspension particles ke size ke. Kai ghanton mein woh dheere-dheere neeche baithte hain, aur doctors ek common blood test mein is settling rate (ESR) ko naapte hain.

5.5 Tyndall Effect

Activity 5.1 ki apni table yaad karo. Beam cheeni wale paani ke andar gayab ho gayi lekin aate wale mixture mein, aur hairaani ki baat, saaf dikhne wale patle doodh mein bhi roshan hui. Kya ho raha tha?

Hum side se beam tabhi dekhte hain jab liquid ke andar kuch uski kuch light ko side mein, hamari aankhon ki taraf bheje. Colloid ya suspension ke particles itne bade hain ki yeh kar sakein: light unse takrati hai aur har direction mein phail jaati hai. Is phailne ko scattering kehte hain. Solution ke ghule particles light ko dhyaan dene layak scatter karne ke liye bahut chhote hain, isliye beam bina dikhe guzar jaati hai. Physicists ise Tyndall effect (टिंडल प्रभाव) kehte hain, John Tyndall ke sammaan mein, ek Irish scientist jinhone 1860s mein iski jaanch ki.

2/3Particles light ko side mein aankh ki taraf scatter karte hain: beam dikhti hai.

Fig. 5.15Tum beam ko side se tabhi dekh sakte ho jab particles uski kuch light tumhari taraf scatter karein.NCERT Fig. 5.23 · p. 87

Left mein ek torch glass tank se beam bhejti hai, aur tank ke neeche ek aankh bani hai jo side se upar dekh rahi hai. Pehle step mein tank mein solution hai: beam seedhi guzar jaati hai, aankh tak koi light nahi pahunchti, aur tank ke andar raasta nahi dikhta. Doosre step mein tank mein colloid hai: beam ke saath kai points se scattered light ke chhote arrows phailte hain, kuch aankh tak pahunchte hain, aur beam ek chamakti band ki tarah dikhti hai. Aakhri step mein ek magnifying circle colloid ka ek particle dikhata hai jis par left se light aati hai aur scattered arrows har direction mein nikalte hain, saath mein chhote ghule particles hain jinke paas se light bina scatter hue guzar jaati hai.

Definition
Tyndall effect

Colloid ya suspension ke particles dwara light beam ka scattering, jisse beam ka raasta dikhne lagta hai.

ExampleFog mein torch ki beam; dhool bhare kamre mein dhoop ki beam.

Ek baar dhyaan doge to Tyndall effect tumhe aksar dikhega. Sardi ki dhundh bhari raat mein car ki headlights roshni ke solid cones jaisi lagti hain. Cinema mein projector ki beam tab dikhti hai jab hall mein dhool ya dhuaan ho. Jungle ya puraane mandir mein, jahan hawa mein dhundh, dhool ya dhuaan ho, wahan gaps se dhoop ki tirchi lakeerein neeche aati hain. Har case mein hawa ki chhoti boondein ya particles light scatter kar rahe hain.

Har colloid ke do partners hote hain. Dispersion medium lagatar faila background substance hai, jaise doodh mein paani. Dispersed phase woh hai jo usmein chhote tukdon mein bikhra hai, jaise doodh mein fat ki boondein. Inke roles solvent aur solute jaise hain, bas bikhre tukde ghule particles se kahin bade hote hain. Table 5.3 mein aur examples hain.

Table 5.3Kuch roz ke colloids ke parts
Dispersed phaseDispersion medium
Doodhfat ki boondein (liquid)paani (liquid)
Fogpaani ki boondein (liquid)air (gas)
Dhuaancarbon ke particles (solid)air (gas)
Shaving foamhawa ke bubbles (gas)saabun wala paani (liquid)
Makkhanpaani ki boondein (liquid)milk fat (naram solid)

Tel ko paani ke saath hilao to boondein jaldi hi judkar upar tairne lagti hain. Phir bhi doodh aur makkhan, jinmein fat aur paani dono hote hain, dinon tak smooth rehte hain. Yeh emulsions hain: aise colloids jinmein ek liquid chhoti boondon ki tarah ek aise doosre liquid mein phaila hota hai jiske saath woh normally nahi milta. Agar tel ki boondein paani mein hon, to yeh oil-in-water emulsion hai, jaise doodh. Agar paani ki boondein fat ya tel mein hon, to yeh water-in-oil emulsion hai, jaise makkhan. Boondon ko alag rakhta hai ek emulsifying agent, jo har boond par ek parat chadha deta hai. Mayonnaise mein egg yolk yeh kaam karta hai, doodh mein natural proteins, aur kapde dhone mein saabun.

Compare

Do tarah ke emulsion

Oil-in-water

  • Tel ki boondein paani mein phaili hain
  • Doodh, mayonnaise, kai face creams
  • Halka lagta hai aur paani se dhul jaata hai

Water-in-oil

  • Paani ki boondein tel mein phaili hain
  • Makkhan, margarine, cold cream
  • Chikna lagta hai aur paani ko rokta hai

Cod-liver oil aur kuch vitamin syrups emulsions ke roop mein bikte hain. Flavoured paani mein tel ki chhoti boondon ki ek chammach, saade tel ki ek chammach se kahin aasaani se li jaati hai.

Practice · 2 questions

Ruko aur socho (NCERT in-text, p. 88): answers ke saath

  1. Short answerMediumNCERT Pause and Ponder Q9

    Punjab mein sardi ki subah ghana fog sadak ko chhupa deta hai. Fog solution hai, suspension hai ya colloid? Iska dispersed phase aur dispersion medium batao, aur ek aisa sign do jo tumhare jawaab ko support kare.

    Solution dikhao

    AnswerEk colloid: air (dispersion medium) mein paani ki boondein (dispersed phase).

    Fog ek colloid hai. Iski chhoti paani ki boondein (dispersed phase) air (dispersion medium) mein phaili hain. Boondein ek-ek karke dekhne ke liye bahut chhoti hain aur neeche baithne ki jagah ghanton tak tairti rehti hain, suspension ki tarah nahi. Phir bhi fog mein headlight beams saaf dikhti hain, isliye boondein light scatter karti hain: yeh Tyndall effect hai, jo true solution kabhi nahi dikhata.

  2. Short answerEasyNCERT Pause and Ponder Q10

    Hall mein dhool ya dhuaan ho to cinema projector ki beam zyada saaf kyun dikhti hai?

    Solution dikhao

    AnswerDhool aur dhuen ke particles projector ki light ko side mein hamari aankhon ki taraf scatter karte hain (Tyndall effect).

    Dhool aur dhuen ke particles itne bade hain ki light scatter kar sakein. Woh projector ki kuch light side mein audience ki taraf bhejte hain, isliye beam ka raasta dikhne lagta hai. Saaf hawa mein light scatter karne ke liye bahut kam cheezein hain, isliye beam mushkil se dikhti hai. Isi kaaran dhuen aur dhool bhari hawa wale shehar dhundhle dikhte hain: particles light ko har direction mein scatter karte hain.

Quick check
3 mein se 1
Ek liquid saaf aur uniform dikhta hai, neeche nahi baithta aur filter paper se guzar jaata hai, lekin uske andar laser beam dikhti hai. Yeh sabse zyada kya ho sakta hai?
Answer dekho

Answer (A) Ek colloid

Sirf colloid filter paper se guzarta hai, kabhi neeche nahi baithta aur light scatter karta hai. Solution mein beam nahi dikhti; suspension neeche baith jaata aur filter use rok leta.

Laboratory ke bahar separation

Is chapter ka har method kisi property ke fark ko use karta hai: size, density, solubility, boiling point ya sublime hone ki kshamata. Kuch mixtures in sab ko maat de dete hain. Masala chai se patti chhaanna aasaan hai; cheeni, doodh aur paani ko alag-alag wapas paana aasaan nahi.

Tumhari body apna khud ka separation plant chalati hai. Kidneys roz blood se lagbhag 180 litre fluid filter karti hain, useful substances ke saath lagbhag saara wapas le leti hain, aur lagbhag dedh litre urine ke roop mein bahar nikaalti hain. Shehar isse bade plants chalate hain: sewage-treatment works screens, settling tanks, coagulants aur filters use karta hai, aur kuch Indian shehar saaf kiya paani power stations ko cooling ke liye bechte hain. Sabse simple separation kitchen ke dustbin par hota hai. Khaane ke bache tukdon ko packaging se alag rakhne se ek compost ban sakta hai aur doosra recycle ho sakta hai. E-waste recyclers isse aage jaate hain, puraane phones se copper, gold aur lithium wapas nikaalte hain. Achhe se kiya gaya har separation matlab landfills mein kam waste.

Quick check
2 mein se 1
Use kiya paper cup aur tooti glass bottle kis bin mein jaani chahiye?
Answer dekho

Answer (C) Blue bin, sookhe waste ke liye

Paper aur glass sookha waste hain jo recycle ho sakta hai, isliye woh blue bin mein jaate hain. Unhe khaane ke waste ke saath milane se compost aur recycling dono kharab hote hain.
Recap

Summary aur key points

  1. Mixtures homogeneous (har jagah same) ya heterogeneous hote hain, aur unhe solutions, suspensions ya colloids mein bhi sort kiya ja sakta hai (Section 5.1).
  2. Concentration solution ki di gayi maatra mein solute ki maatra hai: % m/m, % m/v aur % v/v sab solute ko poore solution ki 100 units se compare karte hain (Section 5.2.2).
  3. Solubility woh sabse zyada solute hai jo 100 g solvent ek diye gaye temperature par ghol sakta hai; zyaadatar solids garam hone par zyada ghulte hain, gases kam (Section 5.2.3).
  4. Crystallization saturated solution se pure solid ko crystals ke roop mein deta hai; impurities bache hue liquid mein rehti hain (Section 5.3.1).
  5. Distillation ek liquid ko boil karke udata hai aur use condense karta hai; simple distillation un miscible liquids ko alag karta hai jinke boiling points mein lagbhag 25 °C ya zyada ka fark ho, aur ghule solid se liquid wapas nikaalta hai (Section 5.3.2).
  6. Fractional distillation paas-paas boiling points wale liquids ko alag karta hai, jaise petroleum refinery mein (Fractional distillation).
  7. Paper chromatography un ghule substances ko alag karta hai jo paper par alag speeds se upar chadhte hain (Section 5.3.3).
  8. Separating funnel immiscible liquids ko density se alag karta hai: zyada dense layer pehle nikaali jaati hai (Section 5.4.1).
  9. Sublimation ek solid ka seedhe vapour mein badalna hai; iska ulta deposition hai. Yeh camphor ya naphthalene ko sublime na hone wale solid se alag karta hai (Section 5.4.2).
  10. Alloys metals ke homogeneous mixtures hain jinhe physical methods alag nahi kar sakte (Alloys).
  11. Centrifugation mixture ko ghumata hai taaki zyada dense particles tube ke neeche jama hon; coagulation alum jaise coagulant se baareek particles ke gucchhe banata hai taaki woh neeche baith jaayein (Section 5.4.3).
  12. Particle size type tay karta hai: solution 1 nm se kam, colloid 1–1000 nm, suspension 1000 nm se zyada (Section 5.4.4).
  13. Colloids aur suspensions light scatter karte hain (Tyndall effect); colloid mein ek dispersed phase dispersion medium mein phaila hota hai (Section 5.5).
Practice · 19 questions

Practice questions answers ke saath (NCERT “Revise karo, socho, behtar banao: exercises”)

  1. Quick answerEasyNCERT Exercises Q1

    In mein se kaunse mixtures heterogeneous hain? Jo bhi hon, saare chuno.

    Saare sahi options chuno
    Answer dekho
    Answer
    • (B) dhuaan
    • (D) ice cream
    • (F) muddy paani
    Dhuen, ice cream aur muddy paani mein particles ya boondein kisi doosre substance mein phaili hoti hain, isliye unka composition jagah-jagah badalta hai. Soda water aur vinegar solutions hain, aur stainless steel alloy hai: teeno homogeneous hain.
  2. Quick answerMediumNCERT Exercises Q2

    In mein se kaunse mixtures Tyndall effect dikhate hain? Jo bhi dikhate hon, saare chuno, aur har choice ka kaaran dene ke liye taiyaar raho.

    Saare sahi options chuno
    Answer dekho
    Answer
    • (A) highway par fog
    • (C) garam paani mein mila gelatin
    • (E) cinema hall ki dhool bhari hawa
    Fog (air mein paani ki boondein) aur paani mein gelatin colloids hain, aur dhool bhari hawa suspension hai; inke particles light scatter karte hain. Glucose aur copper sulfate true solutions banate hain, jinke particles 1 nm se chhote hain, isliye beam bina dikhe guzar jaati hai.
  3. Short answerMediumNCERT Exercises Q3

    Har mixture ko solution, suspension ya colloid mein classify karo.

    1. Ek halka liquid jo kabhi neeche nahi baithta aur filter paper se guzar jaata hai, lekin torch ki beam ka raasta dikhata hai.

      Solution dikhao

      Na neeche baithna aur na residue, isse suspension nahi ho sakta; dikhti beam se solution nahi ho sakta. 1–1000 nm ke particles: ek colloid, jaise patla doodh.

    2. Ek dhundhla liquid jiske particles raat bhar mein neeche baith jaate hain aur filter paper unhe pakad leta hai.

      Solution dikhao

      Neeche baithna aur filter paper par residue dikhate hain ki particles lagbhag 1000 nm se bade hain: ek suspension, jaise paani mein chalk ya mitti.

    3. Ek transparent liquid jo kabhi neeche nahi baithta, filter paper se guzar jaata hai aur koi beam nahi dikhata.

      Solution dikhao

      1 nm se chhote particles har test mein bina dikhe nikal jaate hain: ek true solution, jaise namak wala paani ya vinegar.

    4. Har tarah ke mixture ke do roz ke examples do.

      Solution dikhao

      AnswerSolutions: cheeni wala paani, vinegar. Suspensions: muddy paani, paani mein chalk. Colloids: doodh, fog.

      Solutions: cheeni wala paani, vinegar, soda water. Suspensions: muddy paani, paani mein chalk, paani mein mili ret. Colloids: doodh, fog, shaving foam, jelly.

  4. NumericalMediumNCERT Exercises Q4

    Neeche diye sawaal hal karo.

    1. Chai masala ka 200 g batch 90 g sonth (dry ginger), 60 g elaichi, 30 g kaali mirch aur 20 g laung se banaya jaata hai. Ek sahi method se mixture mein har masale ki maatra express karo.

      Solution dikhao

      AnswerSonth 45 %, elaichi 30 %, kaali mirch 15 %, laung 10 % (sab % m/m).

      Saare parts grams mein tole gaye solids hain, isliye mass by mass percentage use karo. Total 90 + 60 + 30 + 20 = 200 g hai.

      • Sonth: 90 ÷ 200 × 100 = 45 %
      • Elaichi: 60 ÷ 200 × 100 = 30 %
      • Kaali mirch: 30 ÷ 200 × 100 = 15 %
      • Laung: 20 ÷ 200 × 100 = 10 %

      Check: chaaron percentages jodkar 100 % hote hain.

    2. 250 g ka bronze medal mass ke hisaab se 88 % copper hai aur baaki tin. Har metal ka mass nikaalo.

      Solution dikhao

      AnswerCopper 220 g, tin 30 g.

      Copper = 88 ÷ 100 × 250 g = 220 g.

      Tin = 250 g − 220 g = 30 g (ya 250 g ka 12 %).

  5. DiagramMediumNCERT Exercises Q5

    Ek 5 L ke can mein 4.0 kg kerosene hai. Galti se thoda paani can mein chala jaata hai.

    1. Kerosene ki density g/mL mein nikaalo.

      g/mL
      Answer dekho

      Answer 0.8 g/mL

      4.0 kg = 4000 g aur 5 L = 5000 mL, isliye density = 4000 ÷ 5000 = 0.80 g/mL.

    2. Kya paani alag layer banayega? Kaunsa liquid upar hoga, aur kyun?

      Solution dikhao

      AnswerHaan. Kerosene upar wali layer banata hai kyunki woh paani se kam dense hai.

      Kerosene aur paani immiscible hain, isliye woh do layers banate hain. Kerosene (0.80 g/mL) paani (1.0 g/mL) se kam dense hai, isliye woh upar tairta hai aur paani neeche jama hota hai.

    3. Dono layers ko tum kaise alag karoge? Apparatus banao aur label karo.

      Solution dikhao

      AnswerSeparating funnel use karo: neeche wali paani ki layer stopcock se nikaalo, boundary wala hissa phenk do, phir kerosene collect karo.

      Mixture ko stand par clamp kiye separating funnel mein daalo aur baithne do. Stopper nikaalo, stopcock kholo aur paani ko beaker mein nikaalo. Boundary par tap band karo, chhota mila hua hissa phenk do, aur kerosene ko doosre container mein nikaalo.

      Tumhari drawing ke labels: stand aur clamp, stopper, separating funnel, kerosene (upar wali layer), paani (neeche wali layer), stopcock, beaker. Fig. 5.10 se compare karo.

  6. Quick answerMediumNCERT Exercises Q6

    Assertion (A): Colloid ko normal filtration se uske parts mein alag nahi kiya ja sakta. Reason (R): Colloid particles filter paper ke chhedon se chhote hote hain.

    Answer dekho

    Answer (A) A aur R dono sahi hain, aur R, A ko explain karta hai.

    Colloid particles (1–1000 nm) filter paper ke chhedon (hazaaron nanometres) se kahin chhote hote hain, isliye woh seedhe guzar jaate hain. Dono statements sahi hain aur R hi wajah hai ki A hota hai.
  7. Short answerMediumNCERT Exercises Q7

    Har mixture ko alag karne ke liye ek method chuno, aur batao ki woh kis property par depend karta hai.

    1. Har mixture ko uske method se match karo.

      Left mein koi item tap karo, phir right mein uska match.

      Solution dikhao
      • Cream doodh ke baaki hisse se kam dense hai: ghumaane se woh alag hoti hai.
      • Iodine halka garam karne par sublime hota hai; namak nahi.
      • Kerosene aur paani immiscible hain aur density mein alag hain.
      • Dyes paper par alag speeds se upar chadhte hain.
      • Solution thanda hone par copper sulfate ki solubility ghatti hai, isliye pure crystals bante hain.
      • Paani boil hokar udta hai aur condense hota hai; salts boil nahi hote.

    2. Kya in mein se koi method brass ke chhilkon mein copper aur zinc ko alag kar sakta hai? Samjhao.

      Solution dikhao

      AnswerNahi. Brass ek alloy hai, yaani homogeneous mixture, isliye physical methods use alag nahi kar sakte.

      Brass mein copper aur zinc particles ke level par mile hote hain, isliye pakadne ke liye koi alag tukde, layers ya boondein nahi hain. Koi bhi metal in temperatures par na sublime hota hai, na paani mein ghulta hai, na boil hota hai, isliye in mein se koi physical method kaam nahi karta.

  8. DiagramMediumNCERT Exercises Q8

    Liquids X aur Y poori tarah mil jaate hain. X 57 °C par boil hota hai aur Y 98 °C par.

    1. Unhe alag karne ka method suggest karo aur uska kaaran do.

      Solution dikhao

      AnswerSimple distillation, kyunki boiling points mein 41 °C ka fark hai, jo lagbhag 25 °C se zyada hai.

      Gap 98 − 57 = 41 °C hai. Yeh 25 °C se kaafi upar hai, isliye shuru mein X lagbhag akela boil hokar nikalta hai.

    2. Kaunsa liquid pehle jama hota hai, aur us dauraan thermometer kya padhta hai?

      Solution dikhao

      AnswerX pehle jama hota hai; thermometer 57 °C ke paas rehta hai.

      X ka boiling point kam hai, isliye uska vapour pehle condenser tak pahunchta hai, aur thermometer bulb par vapour lagbhag 57 °C par hota hai. X khatam hone par reading 98 °C ki taraf badhti hai.

    3. Apparatus banao aur label karo.

      Solution dikhao

      AnswerLabel: burner, wire gauze aur tripod, mixture wala distillation flask, side arm par thermometer, condenser jismein water in (neeche wala sira) aur water out (upar wala sira), liquid X wala receiver flask.

      Apni drawing ko Fig. 5.8 se compare karo. Thermometer ka bulb side arm par hona chahiye, liquid mein nahi, aur thanda paani condenser mein uske neeche wale sire se aata hai.

  9. Long answerMediumNCERT Exercises Q9

    Tumhare paas teen tools hain: evaporation, crystallization aur distillation. Har ek ke liye batao ki aakhir mein tumhare paas kya bachta hai, aur ek aisa kaam batao jo woh baaki do se behtar karta hai.

    Solution dikhao

    AnswerEvaporation sirf solid rakhta hai; crystallization zyada pure solid rakhta hai; distillation liquid (aur solid) rakhta hai.

    • Evaporation: solvent hawa mein nikal jaata hai aur ghula solid bach jaata hai. Jaldi aur simple, lekin solid purify nahi hota aur solvent kho jaata hai. Ghar par ya salt pans mein salt solution se common salt paane ke liye ise chuno.
    • Crystallization: garam saturated solution thanda hota hai (ya dheere evaporate hota hai) aur pure crystals ugte hain, jabki impurities ghuli rehti hain. Alum, copper sulfate ya cheeni jaise solid ko purify karne ke liye ise chuno, khaaskar aisa solid jo poora sukhane tak garam karne par jal jaata.
    • Distillation: liquid boil hokar udta hai aur condense hota hai, isliye woh pure roop mein wapas milta hai; koi bhi solid peeche reh jaata hai. Sea water se peene ka paani paane ke liye, ya boiling points mein bade gap wale do miscible liquids ko alag karne ke liye ise chuno.
  10. Short answerMediumNCERT Exercises Q10

    Doodh ek colloid hai.

    1. Agar doodh true suspension ki tarah behave karta, to table par ek ghanta rakhe doodh ke glass mein tumhe kya dikhta?

      Solution dikhao

      AnswerParticles neeche ek layer mein baith jaate aur upar ka liquid saaf ho jaata.

      Suspension ke particles itne bade hote hain ki doob jaayein. Doodh ghante bhar mein sediment aur saaf liquid mein alag ho jaata, aur tumhe peene se pehle har glass hilana padta. Asli doodh ek jaisa safed rehta hai kyunki uski fat droplets colloid size ki hain aur neeche nahi baithti.

    2. Doodh mein dispersed phase aur dispersion medium ka naam batao.

      Solution dikhao

      AnswerDispersed phase: fat droplets (protein particles ke saath). Dispersion medium: paani.

      Doodh ek oil-in-water emulsion hai: chhoti fat droplets, protein particles ke saath, paani mein phaili hain.

    3. Ek chammach nimbu ka ras garam doodh ko curds aur whey mein kyun phaad deta hai?

      Solution dikhao

      AnswerAcid doodh ke proteins ko coagulate karta hai, jo curds ke gucchhe ban jaate hain.

      Nimbu ka ras ek acid hai jo coagulant ka kaam karta hai. Yeh chhote protein particles ko chipka kar bade gucchhe banata hai (curds, jo paneer bante hain), aur peeche ek paani jaisa liquid (whey) chhodta hai.

  11. Quick answerMediumNCERT Exercises Q11

    Tumhe camphor, chalk powder aur cheeni ka mixture diya gaya hai. Separation ke steps ko sahi order mein lagao.

    1. Filter karo
    2. Ulte funnel ke neeche garam karo
    3. Filtrate ko crystallize karo
    4. Bache hue ko paani mein milao
    Solution dikhao

    Camphor pehle nikalna chahiye: mixture geela hone ke baad use garam karke camphor ko saaf-saaf collect karna mushkil hai. Cheeni ko poora sukhane tak boil karne ki jagah crystallization se wapas liya jaata hai, kyunki zyada garam karne se woh jal jaati.

  12. Short answerMediumNCERT Exercises Q12

    Methanol 65 °C par boil hota hai aur ethanol 78 °C par; paani 100 °C par boil hota hai. Samjhao ki simple distillation methanol ko paani se achhe se kyun alag karta hai, lekin ethanol ko paani se kyun nahi.

    Solution dikhao

    AnswerMethanol aur paani mein 35 °C ka fark hai (kaafi); ethanol aur paani mein sirf 22 °C (bahut paas), isliye ethanol–water ko fractional distillation chahiye.

    35 °C ke gap ke saath methanol lagbhag akela boil hokar nikalta hai jabki paani zyaadatar liquid rehta hai, isliye distillate lagbhag pure methanol hota hai. Sirf 22 °C ke gap ke saath ethanol ke saath kaafi water vapour bhi nikalta hai, isliye distillate abhi bhi mixture hota hai. Paas-paas boiling points ko fractional distillation chahiye.

  13. NumericalHardNCERT Exercises Q13

    Approximate solubilities ki table use karke jawaab do.

    Table 5.6Solubility, g per 100 g paani mein
    TemperaturePotassium nitrateCheeniCommon salt
    20 °C3220436.0
    40 °C6423836.6
    60 °C11028737.3
    80 °C16936238.4

    1. 60 °C par 25 g paani ko saturate karne ke liye kitna mass cheeni chahiye?

      g
      Answer dekho

      Answer 71.75 g

      287 g × 25 ÷ 100 = 71.75 g, lagbhag 72 g.

    2. 80 °C par 50 g paani mein potassium nitrate ka saturated solution 20 °C tak thanda kiya jaata hai. Kitne mass ke crystals bante hain?

      g
      Answer dekho

      Answer 68.5 g

      Per 100 g paani, 169 − 32 = 137 g bahar aata hai; 50 g paani ke liye uska aadha: 68.5 g.

    3. Ek student common salt ke garam saturated solution ko 80 °C se 20 °C tak thanda karti hai, is ummeed mein ki bahut saare crystals milenge. Use kya dikhega, aur use iski jagah kya karna chahiye?

      Solution dikhao

      AnswerMushkil se koi crystals (per 100 g paani sirf lagbhag 2.4 g). Use iski jagah paani ko evaporate karna chahiye.

      Namak ki solubility sirf 38.4 g se 36.0 g tak girti hai, isliye per 100 g paani bas 2.4 g bahar aata hai. Kyunki thanda karne se iski solubility mushkil se badalti hai, namak ko paani evaporate karke crystallize kiya jaata hai, jaise salt pans mein.

    4. 20 °C se 80 °C tak garam karne ka teeno solubilities par kya asar hota hai? Kaunsi sabse zyada badhti hai?

      Solution dikhao

      AnswerSab badhti hain. Grams mein cheeni sabse zyada badhti hai (+158 g); proportion mein potassium nitrate sabse zyada badhta hai (lagbhag 5 guna); namak mushkil se badalta hai (+2.4 g).

      Cheeni: 362 − 204 = 158 g. Potassium nitrate: 169 − 32 = 137 g, lekin yeh 20 °C wali value ke paanch guna se bhi zyada hai. Common salt: sirf 2.4 g. To zyaadatar solids ki solubility temperature ke saath badhti hai, lekin bahut alag-alag maatra mein.

  14. NumericalMediumNCERT Exercises Q14

    Teen dost sugar syrup banate hain: Ravi 102 g paani mein 18 g cheeni gholta hai, Meena 175 g paani mein 25 g gholti hai, aur Arjun 120 g paani mein 30 g gholta hai.

    1. Har syrup mein cheeni ka % m/m nikaalo.

      Solution dikhao

      AnswerRavi 15 %, Meena 12.5 %, Arjun 20 %.

      • Ravi: 18 ÷ (18 + 102) × 100 = 18 ÷ 120 × 100 = 15 %
      • Meena: 25 ÷ 200 × 100 = 12.5 %
      • Arjun: 30 ÷ 150 × 100 = 20 %

    2. Kiska syrup sabse zyada concentrated hai?

      Answer dekho

      Answer (C) Arjun ka

      Arjun ke syrup mein har 100 g mein 20 g cheeni hai, sabse bada hissa.

    3. Meena ne Ravi se zyada cheeni use ki. Phir bhi uska syrup kamzor kyun hai?

      Solution dikhao

      AnswerConcentration poore solution mein cheeni ke hisse par depend karta hai, aur Meena ne kahin zyada paani use kiya.

      Meena ki 25 g cheeni 200 g solution mein phaili hai (12.5 %), jabki Ravi ki 18 g sirf 120 g mein hai (15 %). Maayne proportion rakhta hai, sirf solute ki maatra nahi.

  15. Short answerHardNCERT Exercises Q15

    Ek set-up mein burner ke upar ek gol flask hai, flask ke side arm par thermometer hai, behte thande paani ke jacket se ghiri ek lambi tirchi tube hai, aur neeche wale sire par liquid collect karta ek flask hai.

    Table 5.7Boiling points
    LiquidPaaniMethanolEthanolAcetic acid
    Boil hone ka temperature (°C)1006578118

    1. Technique ka naam batao aur thermometer aur thande paani wali tube ka kaam batao.

      Solution dikhao

      AnswerDistillation. Thermometer flask se nikalte vapour ka temperature dikhata hai; thande paani wali tube (condenser) vapour ko wapas liquid banati hai.

      Yeh distillation set-up hai. Side arm par laga thermometer batata hai ki kaunsa liquid boil hokar aage jaa raha hai. Condenser vapour ko thanda karta hai taaki woh condense hokar collecting flask mein aaye.

    2. Yeh set-up kaunse mixtures achhe se alag kar sakta hai? Jo bhi sahi hon, saare chuno.

      Saare sahi options chuno
      Answer dekho
      Answer
      • (A) methanol aur paani
      • (C) ethanol aur acetic acid
      • (E) copper sulfate solution se paani
      Methanol–water (35 °C gap) aur ethanol–acetic acid (40 °C gap) achhe se alag hote hain, aur ghule copper sulfate se paani distill hokar nikal jaata hai. Ethanol–water (22 °C) aur methanol–ethanol (13 °C) bahut paas hain aur unhe fractional distillation chahiye.
  16. Quick answerEasy

    3 g namak paani mein ghola jaata hai aur volume 150 mL tak kiya jaata hai. Mass by volume percentage kitna hai?

    %
    Answer dekho

    Answer 2 %

    3 g ÷ 150 mL × 100 = 2 % m/v.
  17. Quick answerEasy

    Jo solid seedhe vapour ban jaata hai, usmein hota hai; vapour ka seedhe wapas solid ban jaana kehlata hai.

    Answer dekho

    Answer (1) sublimation, (2) deposition

    Solid se vapour sublimation hai; vapour se solid deposition hai.
  18. Quick answerEasy

    Paani ke glass ko garam karne se woh zyada dissolved oxygen rakh sakta hai.

    Answer dekho

    Answer Galat

    Paani garam hone par gases kam soluble hoti hain; isiliye garam soda jaldi flat ho jaata hai.
  19. Quick answerEasy

    Colloid ke particles lagbhag kitne bade hote hain?

    Answer dekho

    Answer (B) 1 aur 1000 nm ke beech

    Solutions ke particles 1 nm se kam aur suspensions ke 1000 nm se zyada hote hain; colloids beech mein hain.

Apna NCERT exercise question dhoondo

Hamare practice questions ncert.ai ke liye likhe gaye hain aur NCERT exercises ko follow karte hain. Apni textbook ke question se match karne wala question dhoondo; uska answer uske saath hai.

Tumhari NCERT textbook meinYahan practice question
NCERT Pause and Ponder Q1Ruko aur socho (NCERT in-text, p. 76) · Q1
NCERT Pause and Ponder Q2Ruko aur socho (NCERT in-text, p. 76) · Q2
NCERT Pause and Ponder Q3Ruko aur socho (NCERT in-text, p. 76) · Q3
NCERT Pause and Ponder Q4Ruko aur socho (NCERT in-text, p. 79) · Q4
NCERT Pause and Ponder Q5Ruko aur socho (NCERT in-text, p. 79) · Q5
NCERT Pause and Ponder Q7Ruko aur socho (NCERT in-text, p. 84) · Q7
NCERT Pause and Ponder Q8Ruko aur socho (NCERT in-text, p. 84) · Q8
NCERT Pause and Ponder Q9Ruko aur socho (NCERT in-text, p. 88) · Q9
NCERT Pause and Ponder Q10Ruko aur socho (NCERT in-text, p. 88) · Q10
NCERT Exercises Q1Revise karo, socho, behtar banao: exercises · Q1
NCERT Exercises Q2Revise karo, socho, behtar banao: exercises · Q2
NCERT Exercises Q3Revise karo, socho, behtar banao: exercises · Q3
NCERT Exercises Q4Revise karo, socho, behtar banao: exercises · Q4
NCERT Exercises Q5Revise karo, socho, behtar banao: exercises · Q5
NCERT Exercises Q6Revise karo, socho, behtar banao: exercises · Q6
NCERT Exercises Q7Revise karo, socho, behtar banao: exercises · Q7
NCERT Exercises Q8Revise karo, socho, behtar banao: exercises · Q8
NCERT Exercises Q9Revise karo, socho, behtar banao: exercises · Q9
NCERT Exercises Q10Revise karo, socho, behtar banao: exercises · Q10
NCERT Exercises Q11Revise karo, socho, behtar banao: exercises · Q11
NCERT Exercises Q12Revise karo, socho, behtar banao: exercises · Q12
NCERT Exercises Q13Revise karo, socho, behtar banao: exercises · Q13
NCERT Exercises Q14Revise karo, socho, behtar banao: exercises · Q14
NCERT Exercises Q15Revise karo, socho, behtar banao: exercises · Q15

Quick check: MCQs

  1. 5.1 Mixtures ko Classify Kaise Karein?3 questions
  2. C. Volume by volume percentage, yaani % v/v3 questions
  3. 5.2.3 Substances ki solubility3 questions
  4. 5.3.1 Crystallization3 questions
  5. 5.3.2 Distillation3 questions
  6. True ya false? (NCERT Pause and Ponder 6)4 questions
  7. 5.4.1 Do immiscible liquids ka separation2 questions
  8. Metals ko milana: alloys2 questions
  9. B. Coagulation3 questions
  10. 5.5 Tyndall Effect3 questions
  11. Laboratory ke bahar separation2 questions
Glossary · 15

Key terms (English + Hindi)

coagulationस्कंदनskandan
Chhote suspended particles ko gucchhon mein jodna, aksar alum jaisa coagulant daal kar, taaki woh neeche baith jaayein.Chapter mein pehli baar yahan aaya →
colloidकोलॉइडkolloid
Lagbhag 1 se 1000 nm ke particles wala heterogeneous mixture, jiske particles phaile rehte hain aur light scatter karte hain.Chapter mein pehli baar yahan aaya →
concentrationसांद्रताsaandrata
Solution (ya solvent) ki di gayi maatra mein kitna solute hai, aksar percentage mein.Chapter mein pehli baar yahan aaya →
crystallizationक्रिस्टलीकरणkristalikaran
Saturated solution se pure solid ko crystals ke roop mein alag karna, aam taur par dheere thanda karke ya dheere evaporate karke.Chapter mein pehli baar yahan aaya →
distillationआसवनaasavan
Mixture se ek liquid ko boil karke nikaalna aur uske vapour ko alag bartan mein condense karke pure liquid banana.Chapter mein pehli baar yahan aaya →
heterogeneous mixtureविषमांगी मिश्रणvishamaangi mishran
Aisa mixture jiska composition jagah-jagah badalta hai, jaise paani mein ret ya paani par tel.Chapter mein pehli baar yahan aaya →
homogeneous mixtureसमांगी मिश्रणsamaangi mishran
Aisa mixture jiska composition har jagah same ho, isliye uske parts alag nahi pehchane ja sakte, jaise cheeni wala paani ya air.Chapter mein pehli baar yahan aaya →
immiscible liquidsअमिश्रणीय द्रवamishraniya drav
Aise liquids jo milte nahi aur alag layers mein baith jaate hain, jaise tel aur paani.Chapter mein pehli baar yahan aaya →
paper chromatographyक्रोमैटोग्राफीkromaitografi
Mixture ke ghule parts ko alag karna, jab solvent unhe paper strip par alag speeds se upar le jaata hai.Chapter mein pehli baar yahan aaya →
saturated solutionसंतृप्त विलयनsantript vilayan
Aisa solution jismein us temperature par jitna ho sake utna solute ghula ho; extra solute bina ghule rehta hai.Chapter mein pehli baar yahan aaya →
solubilityविलेयताvileyata
Ek diye gaye temperature par 100 g solvent mein ghulne wala solute ka sabse zyada mass.Chapter mein pehli baar yahan aaya →
solutionविलयनvilayan
Ek solute (jo substance ghulta hai) aur ek solvent (jismein woh ghulta hai) ka homogeneous mixture.Chapter mein pehli baar yahan aaya →
sublimationऊर्ध्वपातनurdhvapaatan
Garam karne par solid ka bina pighle seedhe vapour ban jaana. Ulta change deposition kehlata hai.Chapter mein pehli baar yahan aaya →
suspensionनिलंबनnilamban
Aisa heterogeneous mixture jiske bina ghule particles dikhne layak bade hon aur rakhe rehne par neeche baith jaayein.Chapter mein pehli baar yahan aaya →
Tyndall effectटिंडल प्रभावtindal prabhav
Colloid ya suspension ke particles dwara light beam ka scattering, jisse beam ka raasta dikhne lagta hai.Chapter mein pehli baar yahan aaya →

Tum chapter ke end tak pahunch gaye