Carbon and its Compounds: Class 10 Science Chapter 4 Hinglish mein

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

Published 12 Oct 2026 · Updated 12 Oct 2026

105 min
32 practice questions
24 MCQs

Is chapter mein aap kya seekhenge

Samjho ki carbon covalent bonds kyun banata hai, aur single, double aur triple bonds wale molecules ke electron-dot structures banao
Diamond, graphite aur fullerenes ke structures ko unki properties se jodo
Catenation aur tetravalency se carbon compounds ki variety samjhao, aur saturated aur unsaturated chains, branches, rings aur isomers mein fark pehchano
Functional groups aur homologous series pehchano, aur simple carbon compounds ke naam IUPAC rules se rakho
Combustion, oxidation, addition aur substitution reactions ko balanced equations ke saath samjhao
Ethanol aur ethanoic acid ki properties aur reactions samjhao, esterification aur saponification ke saath
Samjhao ki soaps aur detergents micelles ke zariye kaise saaf karte hain, aur hard water mein soap scum kyun banata hai

NCERT Science Class 10, Chapter 4, pp. 58–78 par based original companion text. Yeh NCERT se juda nahi hai aur NCERT ne ise endorse nahi kiya hai.

Apni kitchen ki cheezon ki ek jaldi si list banao: cylinder mein LPG, chawal aur dal, ek plastic ki balti, ek cotton ka bartan wala kapda. Yeh dikhne aur behave karne mein bilkul alag hain, phir bhi lagbhag sab ek hi element se bane hain, carbon (कार्बन).

Carbon common nahi hai. Earth ke crust ka yeh sirf lagbhag 0.02 % hai, aur zyaadatar coal, petroleum aur limestone jaise carbonate rocks mein band hai. Hawa mein carbon dioxide lagbhag 0.04 % hai. Phir bhi har living cell, tulsi ki patti se lekar tumhari apni skin tak, carbon compounds se bana hai. Yeh chapter poochta hai ki carbon itna special kyun hai, aur phir un carbon compounds ko dekhta hai jinse tum roz milte ho: fuels, alcohol, vinegar, soaps aur detergents.

Activity 4.1NCERT Activity 4.1 · p. 58

Tumhari subah kis cheez se bani hai?

Tumhe chahiye

ek notebook aur pen
do ya teen classmates

Pehle guess karo

Aaj subah tumne jo kuch use kiya, use teen groups mein baanto. Tumhe kaunsa group sabse bada lagta hai?

Metal se bani cheezeinGlass ya mitti se bani cheezeinBaaki sab: khana, kapda, paper, plastic, lakdi

Uthne se lekar school pahunchne tak tumne jo baarah cheezein use ki ya khaayi, unhe likho: toothpaste, chai, steel ka glass, tumhari uniform, ek notebook wagairah.
Apni lists ko do ya teen classmates ke saath milao.
Har item ko table mein sort karo. Agar koi item do materials se bana hai, jaise plastic handle wala pressure cooker, to dono columns par tick karo.

Table 4.1Apne items sort karo

Item	Metal	Glass ya mitti	Kuch aur

Tumhari entries apne aap save hoti hain.

4.1 Carbon mein Bonding – Covalent Bond

Chapter 3 mein tum common salt jaise ionic compounds se mile the: hard solids jo sirf bahut garam hone par pighalte hain aur pighle ya ghule hone par electricity conduct karte hain. Carbon compounds bilkul alag tarah behave karte hain. Inmein se zyaadatar gases, liquids ya soft solids hain jo aasaani se pighal jaate hain, aur lagbhag koi bhi electricity conduct nahi karta. Table 4.2 mein numbers compare karo.

Table 4.2Carbon compounds ionic compound se kahin neeche pighalte aur ubalte hain

Compound	Yeh kahan milta hai	Melting point (°C)	Boiling point (°C)
Butane, $C_{4} H_{10}$	LPG cylinder	−138	−0.5
Propanone, $C H_{3} C O C H_{3}$	nail-polish remover	−95	56
Ethanol, $C_{2} H_{5} O H$	hand sanitiser	−114	78
Naphthalene, $C_{10} H_{8}$	mothballs (naphthalene ki goliyan)	80	218
Sodium chloride, $N a C l$ (ionic)	khaane ka namak	801	1465

Yeh numbers humein kya batate hain? Kisi substance ko pighlaane ya ubaalne ke liye heat ko uske particles ko ek doosre se door kheenchna padta hai. Salt ko 800 °C se zyaada chahiye kyunki uske ions strong attractions se jakde hue hain. LPG ko lagbhag koi heat nahi chahiye, to uske molecules ek doosre se bas dheele-dheele chipke ho sakte hain. Aur jo substance current nahi le jaata, usmein free ions nahi hote. Carbon compound ke atoms ko jo bhi jodkar rakhta hai, woh ions banane wala electron transfer nahi hai.

Carbon ka atomic number 6 hai, isliye uske electrons K shell mein 2 aur L shell mein 4 ki tarah arranged hain. Chaar valence electrons ke saath woh octet ke theek aadhe raaste par hai, aur use poora karne ke dono seedhe raaste band hain:

Chaar le le? Ion $C^{4 -}$ mein das electrons honge lekin unhe attract karne ke liye sirf chhe protons. Chaar naye electrons itne dheele pakde jaayenge ki ion tik hi nahi paayega.
Chaar kho de? Har electron hataane par agla electron kheenchna aur mushkil ho jaata hai. Chaaron ko hataakar sirf do electrons wala chhota sa $C^{4 +}$ ion banaane mein bahut zyaada energy lagegi.

2/3 $C^{4 -}$ banne par chhe protons ko das electrons pakadne padenge.

Fig. 4.1Carbon aadhe raaste mein atka hai: chaar electrons lena ya khona, dono bahut mehenge hain.NCERT p. 59

Carbon atom ko ek nucleus ki tarah banaya gaya hai jis par 6+ likha hai, inner shell mein do electrons aur outer shell mein chaar. Step 1 mein us par carbon, atomic number 6, shells 2, 4, aur chaar valence electrons likha hai. Step 2 mein outer shell par crosses ki tarah chaar extra electrons jodkar C4− banta hai, aur note batata hai ki chhe protons ko das electrons pakadne padenge, jo pakad bahut kamzor hai. Step 3 mein chaar outer electrons door jaate hain aur C4+ bachta hai, aur note batata hai ki unhe kheenchkar hataane mein bahut zyaada energy lagti hai.

Carbon teesra raasta leta hai: woh share karta hai. Socho do padosi ek joint gullak mein ek-ek sikka daalte hain; dono us gullak ko apna maan sakte hain. Isi tarah do atoms ek-ek electron ek pair mein daal sakte hain jo unke beech rehta hai, aur dono us pair ko apne outer shell mein ginte hain. Hydrogen, oxygen, nitrogen aur chlorine bhi aise hi bond banate hain, aur unke chhote molecules yeh idea sabse saaf dikhate hain. Padhte-padhte Fig. 4.2 ke steps dekho.

Hydrogen, $H_{2}$ . Hydrogen atom mein ek electron hota hai aur helium ke full K shell jaisa banne ke liye use ek aur chahiye. Do hydrogen atoms apna-apna electron ek shared pair mein daalte hain, aur dono satisfied ho jaate hain. Ek shared pair ek single covalent bond hai, jise ek line se dikhate hain: $H - H$ .

Oxygen, $O_{2}$ . Oxygen (2, 6) octet se do electrons peeche hai. Har atom do electrons apne beech ki jagah mein daalta hai, aur do shared pairs bante hain: ek double bond, $O = O$ . Har oxygen do pairs apne paas bhi rakhta hai, jinhe lone pairs kehte hain.

Nitrogen, $N_{2}$ . Nitrogen (2, 5) ko teen aur electrons chahiye, isliye har atom teen electrons beech mein daalta hai. Teen shared pairs se ek triple bond banta hai, $N \equiv N$ . Yeh bond bahut strong hai, aur yahi ek wajah hai ki hawa ka nitrogen itna unreactive hai.

Methane, $C H_{4}$ . Methane CNG ki aur gobar gas plant se bani biogas ki main gas hai. Iska carbon chaar hydrogen atoms mein se har ek ke saath ek pair share karta hai, isliye carbon ke aas-paas aath electrons hote hain aur har hydrogen ke paas do. Kyunki carbon apne compounds mein chaar bonds banata hai, hum kehte hain ki woh tetravalent hai.

4/4 $C H_{4}$ : carbon chaar H atoms mein se har ek ke saath ek pair share karta hai.

Fig. 4.2Shared pairs (shaded) bond lines ban jaate hain: ek, do ya teen pairs se single, double ya triple bonds bante hain.NCERT Figs 4.1–4.5 · p. 60

Har step mein ek molecule left mein electron-dot structure ki tarah aur right mein bond-line formula ki tarah dikhta hai. Ek atom ke electrons dots hain aur doosre ke crosses; shared pairs atoms ke beech shaded bands mein hain. Step 1: H2, ek shared pair, single bond H–H. Step 2: O2, do shared pairs aur har oxygen par do lone pairs, ek double bond. Step 3: N2, teen shared pairs aur har nitrogen par ek lone pair, ek triple bond. Step 4: CH4, carbon chaar hydrogen atoms mein se har ek ke saath ek pair share karta hai, jise chaar single bonds ki tarah banaya gaya hai.

Definition

Covalent bond

Woh bond jo tab banta hai jab do atoms electrons ka ek pair share karte hain, taaki har atom ka stable, full outer shell ban jaaye. Atoms ek, do ya teen pairs share kar sakte hain.

Example $H - H$ (ek pair), $O = O$ (do pairs), $N \equiv N$ (teen pairs).

Covalent compounds itni aasaani se kyun pighalte hain? Footballs se bhare ek jaali wale bag ke baare mein socho. Har ball khud mazbooti se sili hui hai, lekin balls ek doosre se bas dheele-dheele tiki hain, isliye unhe bahar ulatna aasaan hai. Isi tarah molecule ke andar ke covalent bonds strong hote hain, lekin molecules ke beech ke forces weak hote hain. Molecules ko alag karne ke liye thodi si heat kaafi hai, isliye melting aur boiling points kam hote hain. Aur kyunki sharing se ions nahi bante, yeh compounds aam taur par electricity ke poor conductors hote hain.

Try karke dekho

Ab tumhari baari: chaar aur molecules

Chlorine ( $C l_{2}$ ; Cl hai 2, 8, 7), water ( $H_{2} O$ ), ammonia ( $N H_{3}$ ; N hai 2, 5) aur carbon dioxide ( $C O_{2}$ ) ke electron-dot structures banao. Sirf valence electrons dikhao. Tay karo ki har bond single hai, double ya triple, phir answer kholo.

Fig. 4.3Answers: chlorine, water aur ammonia mein single bonds hain; carbon dioxide mein do double bonds hain.NCERT p. 60

Ek grid mein chaar electron-dot structures, shared pairs shaded bands mein. Chlorine, Cl2: ek shared pair aur har chlorine par teen lone pairs. Water, H2O: oxygen har hydrogen ke saath ek pair share karta hai aur do lone pairs rakhta hai. Ammonia, NH3: nitrogen teen hydrogens mein se har ek ke saath ek pair share karta hai aur ek lone pair rakhta hai. Carbon dioxide, CO2: carbon har oxygen ke saath do pairs share karta hai, aur har oxygen do lone pairs rakhta hai.

Chlorine aur water mein sirf single bonds hain. Ammonia mein teen single bonds aur nitrogen par ek lone pair hai. Carbon dioxide mein do double bonds hain, $O = C = O$ , to carbon phir se chaar bonds banata hai.

Example 4.1

Methanal ke electron dots

Methanal, $H C H O$ , woh gas hai jo formalin mein ghuli hoti hai, aur biology lab mein specimens ko preserve karne ke kaam aati hai. Iska carbon do hydrogen atoms aur ek oxygen atom se bonded hai. Iska electron-dot structure banao aur batao ki C aur O ke beech kis tarah ka bond hai.

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

Carbon ke Allotropes

Pure carbon khud kai roop mein milta hai. Ring mein laga diamond, tumhari pencil ka graphite wala "lead" aur lamp ki chimney par jami kaalikh, sab sirf carbon atoms hain. Ek hi element ke alag roop, jinmein atoms alag tarah se arranged hote hain, allotropes kehlaate hain.

Definition

Allotropes

Ek hi element ke alag roop jinmein atoms alag arrangements mein bonded hote hain.

ExampleDiamond, graphite aur fullerenes carbon ke allotropes hain.

Diamond ke atoms har direction mein jude hote hain. Har carbon chaar neighbours ko pakadta hai jo ek tetrahedron ke corners par hote hain, woh neighbours chaar aur ko pakadte hain, aur aise hi poore crystal mein: ek giant, rigid three-dimensional network. Isi wajah se diamond sabse hard natural substance hai. Yeh electricity conduct nahi karta, kyunki har valence electron ek bond mein bandha hai.

Graphite flat sheets mein bana hota hai. Ek sheet mein har carbon sirf teen neighbours se juda hota hai, aur hexagons ka ek honeycomb banta hai. Carbon ki valency chaar rakhne ke liye un teen links mein se ek ko double bond maana jaata hai. Sheets ek kitaab ke pages ki tarah dheele-dheele ek ke upar ek rakhi hoti hain, aur aasaani se ek doosre par slide karti hain. Isliye graphite soft aur chikna hota hai: yeh paper par nishaan chhodta hai aur lubricant ka kaam karta hai. Electrons sheets ke saath-saath chal sakte hain, isliye graphite, ek non-metal hote hue bhi, electricity conduct karta hai aur electrodes mein use hota hai.

2/3Har C teen se bonded, flat sheets mein jo slide karti hain.

Fig. 4.4Same atoms, alag arrangements: diamond, graphite aur

C_{60}

.NCERT Aur Jaano · p. 61

Step 1, diamond: ek carbon atom chaar neighbours se bonded hai, aur har neighbour aage aur atoms se bond karta hai, jisse ek rigid three-dimensional network banta hai; labels batate hain ki har carbon chaar se bonded hai, yeh sabse hard natural solid hai aur conduct nahi karta. Step 2, graphite: hexagonal rings ki ek flat layer aur teen stacked layers ka side view, jismein beech wali layer khiski hui hai taaki sliding dikhe; labels batate hain ki har carbon sheets mein teen se bonded hai aur graphite electricity conduct karta hai. Step 3, fullerene: pentagons aur hexagons se bani 60 carbon atoms ki ek khokhli ball, football jaisi.

Compare

Diamond aur graphite

Diamond

Har C 4 aur se bonded
Rigid 3-D network
Sabse hard natural substance
Electricity conduct nahi karta
Jewellery, cutting aur drilling tools

Graphite

Har C ek plane mein 3 aur se bonded
Hexagons ki layers jo slide karti hain
Soft aur chikna
Electricity ka achha conductor
Pencils, lubricants, electrodes

Kyunki dono pure carbon hain, diamond aur graphite ki chemical properties same hain: dono bhar-poor oxygen mein jalkar sirf carbon dioxide dete hain. Unki physical properties alag hain kyunki unke atoms alag tarah se arranged hain.

Quick check

4 mein se 1

Carbon ions ki jagah covalent bonds kyun banata hai?

Uske paas itne kam protons hain ki woh koi electron attract hi nahi kar saktaCarbon atoms ions banane ke liye bahut bade hainUska outer shell pehle se full haiChaar electrons lena ya khona bahut mushkil hai, isliye woh share karta hai

Answer dekho

Answer (D) Chaar electrons lena ya khona bahut mushkil hai, isliye woh share karta hai

Chaar valence electrons ke saath carbon ko chaar electrons lene ya khone padenge.

C^{4 -}

ion apne extra electrons ko bahut kamzori se pakadta hai, aur

C^{4 +}

banane mein bahut zyaada energy lagti hai, isliye carbon share karta hai. Asal mein carbon ek chhota atom hai.

Practice · 2 questions

Practice 4.1 (NCERT ke in-text questions, p. 61): answers ke saath

Short answerMediumNCERT in-text Q1, p. 61
Carbon disulphide, $C S_{2}$ , ek liquid hai jo viscose rayon banane mein use hota hai. Sulphur (2, 8, 6) ke oxygen ki tarah chhe valence electrons hain. $C S_{2}$ ka electron-dot structure banao aur har bond ka type batao.
Solution dikhao
Answer $S = C = S$ : do double bonds; har S do lone pairs rakhta hai.
Carbon ke 4 valence electrons hain aur har S ke 6. Carbon har sulphur ke saath do pairs share karta hai, isliye uske 4 shared pairs (8 electrons) hain. Har sulphur ke 2 shared pairs aur 2 lone pairs hain, yaani yeh bhi 8.
Check: $4 + 6 + 6 = 16$ electrons, yaani 8 pairs: 4 bonding aur 4 lone ✓. Structure hai $S = C = S$ , bilkul $O = C = O$ jaisa.
Short answerMediumNCERT in-text Q2, p. 61
Sulphur rings bhi banata hai. Chhe sulphur atoms ki ring, $S_{6}$ , ka electron-dot structure banao. Is molecule mein kitne shared pairs aur lone pairs hain?
Solution dikhao
Answer6 shared pairs (single bonds) aur 12 lone pairs.
Sulphur ko do aur electrons chahiye, isliye woh do single bonds banata hai, ring mein har neighbour ke saath ek. Ring mein chhe atoms se chhe S–S bonds bante hain.
Har S apne 6 valence electrons mein se 2 bonds mein use karta hai aur 4 ko do lone pairs ki tarah rakhta hai: $6 \times 2 = 12$ lone pairs. Check: 36 electrons = 18 pairs = 6 + 12 ✓.

4.2 Carbon ka Versatile Nature

Chemists ne aaj tak jitne bhi substances describe kiye hain, unki list banao, to zyaadatar entries mein, jo millions mein hain, carbon hoga. Baaki sau ke aas-paas elements milkar bhi kahin kam compounds banate hain. Tumhara shareer, tumhara khana aur tumhare kapde carbon compounds hain. Ek element itna kuch kaise bana leta hai? Iski do properties milkar kaam karti hain.

(i) Catenation. Carbon atoms ek doosre se strong bonds banate hain. Kyunki har carbon chaar tak doosre carbons se jud sakta hai, carbon saikdon ya hazaaron atoms lambi chains, side branches wali chains, aur band rings banata hai. Is self-linking ko catenation kehte hain. Carbons ke beech ke links single, double ya triple bonds ho sakte hain, aur yahi fark Section 4.2.1 mein compounds ko do kinds mein baantta hai.

Carbon ka sabse kareebi rival silicon hai, jo periodic table mein uske neeche wala element hai. Silicon–hydrogen compounds lagbhag saat ya aath silicon atoms ki chains par ruk jaate hain, aur yeh bhi aasaani se toot jaate hain ya aag pakad lete hain. Carbon–carbon bonds strong aur stable hote hain, isiliye plastics aur starch ki chains itni lambi ho sakti hain.

Definition

Catenation

Kisi element ke atoms ki ek doosre se bond banakar lambi chains, branches ya rings banane ki ability. Carbon mein yeh kisi bhi aur element se zyaada hoti hai.

(ii) Tetravalency. Har carbon atom ke paas dene ke liye chaar bonds hote hain. Woh inhe doosre carbons par, ya hydrogen, oxygen, nitrogen, sulphur, chlorine wagairah par laga sakta hai, aur har naya partner compound ka behaviour badal deta hai. Yeh bonds tikte bhi hain. Carbon atom chhota hota hai, isliye shared electrons uske nucleus ke paas rehte hain aur mazbooti se pakde jaate hain. Bade atoms mein shared pairs door rehte hain aur bonds weak hote hain.

Definition

Tetravalency

Valency chaar hona. Carbon atom chaar covalent bonds banata hai.

4.2.1 Saturated aur Unsaturated Carbon Compounds

Kisi carbon compound ka structure uske formula se kaise nikaalein? Ethane, $C_{2} H_{6}$ , lo. Pehle do carbon atoms ko single bond se jodo. Ab har carbon ki teen valencies bachi hain. Har ek mein ek hydrogen atom bharo, aur chhe ke chhe hydrogens use ho jaate hain. Yeh dekhne ke liye Fig. 4.5 ke steps dekho, uske neeche matching electron-dot structure ke saath.

3/4Sirf chaar H ke saath har carbon ki ek valency bachti hai, isliye carbons ek doosra pair share karte hain: $C_{2} H_{4}$ .

Fig. 4.5Pehle carbons jodo, phir free valencies bharo; jo valency bach jaaye woh ek aur C–C bond ban jaati hai.NCERT Figs 4.6–4.7 · p. 63

Upar wale hisse mein bond-line structures hain aur neeche wale mein electron-dot structures, carbon ke electrons dots aur hydrogen ke electrons crosses hain. Step 1: do carbon atoms single bond se jude hain, har carbon par teen free valencies ke liye dashed stubs aur teen unpaired electrons. Step 2: ethane, C2H6, har carbon teen hydrogens se bonded, saat shared pairs, saturated. Step 3: ethene, C2H4, har carbon par do hydrogens, isliye carbons do pairs share karte hain, ek double bond; chhe shared pairs. Step 4: ethyne, C2H2, har carbon par ek hydrogen aur ek triple bond; paanch shared pairs.

Propane, $C_{3} H_{8}$ , ko bhi isi tarah try karo. Chain $C - C - C$ mein 3 + 2 + 3 = 8 free valencies bachti hain, theek aath hydrogens ke liye kaafi: $C H_{3} - C H_{2} - C H_{3}$ . Har bond single hone se propane saturated hai, aur baaki saturated compounds ki tarah yeh bhi mushkil se react karta hai.

Ethene, $C_{2} H_{4}$ , mein ethane se do hydrogens kam hain. Iske chaar hydrogens lagne ke baad bhi har carbon ka ek bond kam padta hai, aur dono carbons ek doosre ke saath ek doosra pair share karke ise theek karte hain: $C H_{2} = C H_{2}$ . Ethyne, $C_{2} H_{2}$ , mein har carbon ke do bonds kam hain, isliye uske carbons teen pairs share karte hain: $H C \equiv C H$ . Ethene aur ethyne unsaturated hain. Unke double aur triple bonds unhe saturated compounds se zyaada reactive banate hain, jaisa tum Section 4.3.3 mein dekhoge.

Definition

Saturated compound

Aisa carbon compound jismein carbon atoms sirf single bonds se jude hote hain.

ExampleEthane, $C H_{3} - C H_{3}$ ; propane, $C H_{3} - C H_{2} - C H_{3}$ .

Definition

Unsaturated compound

Aisa carbon compound jismein carbon atoms ke beech kam se kam ek double ya triple bond ho.

ExampleEthene, $C H_{2} = C H_{2}$ ; ethyne, $H C \equiv C H$ .

4.2.2 Chains, Branches aur Rings

Carbon chain ko teen atoms par kuch nahi rokta. Table 4.3 saturated carbon–hydrogen compounds ki family ko chhe carbons tak le jaata hai. Dekho chain badhne ke saath boiling point kaise chadhta hai.

Table 4.3Pehle chhe alkanes

Name	Formula	Condensed formula	Boiling point (°C)	25 °C par
Methane	$C H_{4}$	$C H_{4}$	−162	gas
Ethane	$C_{2} H_{6}$	$C H_{3} C H_{3}$	−89	gas
Propane	$C_{3} H_{8}$	$C H_{3} C H_{2} C H_{3}$	−42	gas
Butane	$C_{4} H_{10}$	$C H_{3} (C H_{2})_{2} C H_{3}$	−0.5	gas
Pentane	$C_{5} H_{12}$	$C H_{3} (C H_{2})_{3} C H_{3}$	36	liquid
Hexane	$C_{6} H_{14}$	$C H_{3} (C H_{2})_{4} C H_{3}$	69	liquid

Butane ko phir se dekho. Chaar carbon atoms ko do tarah se joda ja sakta hai. Woh ek seedhi lagaataar chain bana sakte hain, ya teen ki chain jismein chautha carbon beech wale par laga ho. Hydrogens bharne par same formula, $C_{4} H_{10}$ , wale do alag molecules milte hain. Pehla butane hai; doosre ko 2-methylpropane (ya isobutane) kehte hain. Aise molecules, jinka molecular formula ek hai lekin bane alag tarah se hain, structural isomers kehlaate hain.

Definition

Structural isomers

Aise compounds jinka molecular formula same ho lekin atoms ka arrangement alag ho.

ExampleButane aur 2-methylpropane, dono $C_{4} H_{10}$ .

Carbon chains band hokar rings bhi ban sakti hain. Ring mein chhe carbons, har ek par do hydrogens, se cyclohexane, $C_{6} H_{12}$ , banta hai, jo ek saturated ring hai. Benzene, $C_{6} H_{6}$ , bhi chhe carbons ki ring hai, lekin har carbon par sirf ek hydrogen hai. Isliye ring mein ek chhod ek jagah par teen double bonds hain aur yeh unsaturated hai. To "chain ya ring" aur "saturated ya unsaturated" do alag sawaal hain jo tum kisi bhi carbon compound ke baare mein pooch sakte ho.

2/42-methylpropane: wahi $C_{4} H_{10}$ ek branch ke saath, butane ka isomer.

Fig. 4.6Ek seedhi chain, ek branched chain aur do rings. Butane aur 2-methylpropane isomers hain.NCERT Figs 4.8–4.10 · p. 65

Carbon atoms letter C se dikhaye gaye hain jo bonds se jude hain; rings mein hydrogen atoms nahi dikhaye gaye. Step 1: butane, chaar carbons ki ek zigzag chain, formula C4H10, condensed CH3–CH2–CH2–CH3. Step 2: 2-methylpropane, ek line mein teen carbons aur chautha beech wale se juda, yeh bhi C4H10, jis par same formula likha hai. Step 3: cyclohexane, ek hexagon mein chhe carbons single bonds ke saath, C6H12, ek saturated ring. Step 4: benzene, teen alternate double bonds wala chhe-carbon hexagon, C6H6, ek unsaturated ring.

Sirf carbon aur hydrogen se bane compounds ko hydrocarbons kehte hain. Yeh teen families mein aate hain:

Compare

Hydrocarbons ki teen families

Alkanes

Sirf single C–C bonds (saturated)
Naam -ane par khatam hote hain
Methane, $C H_{4}$

Alkenes

Kam se kam ek C=C double bond
Naam -ene par khatam hote hain
Ethene, $C_{2} H_{4}$

Alkynes

Kam se kam ek C≡C triple bond
Naam -yne par khatam hote hain
Ethyne, $C_{2} H_{2}$

4.2.3 Kya Tum Mere Dost Banoge?

Carbon ke dost sirf hydrogen atoms nahi hain. Chain par ek hydrogen ko chlorine atom se, ya hydrogen wale oxygen se badal do, aur tumhe nayi aadaton wala ek naya compound mil jaata hai. Bas ek rule hai: har carbon ke aakhir mein chaar bonds hi hone chahiye. Chlorine, bromine, oxygen, nitrogen aur sulphur jaise atoms, jo hydrogen ki jagah carbon compound mein lagte hain, heteroatoms kehlaate hain, yaani "doosre atoms".

Methanol aur butanol molecules ka size alag hai, phir bhi dono sodium ke saath fizz karte hain aur dono oxidise hokar acids ban sakte hain. Inmein common hai –OH group. Koi atom ya atoms ka chhota group jo compound ki chemistry tay karta hai, chahe woh kisi bhi chain par laga ho, functional group kehlaata hai. Table 4.4 mein har group par laga dash woh bond hai jo use chain se jodta hai, jahan pehle ek hydrogen tha.

Definition

Functional group

Carbon chain se juda ek atom ya atoms ka group jo compound ki chemical properties tay karta hai.

ExampleAlcohols mein –OH, carboxylic acids mein –COOH.

Table 4.4Common functional groups

Heteroatom	Compound ki class	Functional group	Example
Cl ya Br	Haloalkane	–Cl, –Br	chloroethane, $C H_{3} C H_{2} C l$
Oxygen	Alcohol	–OH	ethanol, $C H_{3} C H_{2} O H$
Oxygen	Aldehyde	–CHO	ethanal, $C H_{3} C H O$
Oxygen	Ketone	Chain ke andar C=O	propanone, $C H_{3} C O C H_{3}$
Oxygen	Carboxylic acid	–COOH	ethanoic acid, $C H_{3} C O O H$

6/6End wala carbon –COOH ban jaata hai: butanoic acid.

Fig. 4.7Group badlo to family aur naam badal jaate hain. Har carbon ke chaar bonds bane rehte hain.NCERT Tables 4.3–4.4 · p. 66

Butane chain jismein har atom dikhaya gaya hai. Har step mein right-hand end par, ya doosre carbon par, laga group badalta hai aur highlight hota hai, aur neeche naam aur formula bhi badalte hain. Step 1: butane, C4H10, ek alkane. Step 2: end ka ek hydrogen chlorine se badla, 1-chlorobutane, C4H9Cl. Step 3: ek –OH group, butan-1-ol, C4H10O, ek alcohol. Step 4: end carbon par ek double-bonded oxygen aur ek hydrogen, butanal, C4H8O, ek aldehyde. Step 5: double-bonded oxygen ab doosre carbon par hai, butanone, C4H8O, ek ketone. Step 6: end carbon par ek double-bonded oxygen aur ek –OH, butanoic acid, C4H8O2, ek carboxylic acid.

4.2.4 Homologous Series

Chloroalkanes $C H_{3} C l$ , $C_{2} H_{5} C l$ , $C_{3} H_{7} C l$ aur $C_{4} H_{9} C l$ ko line mein rakho. Har ek par same –Cl group hai, aur har chain pichhli se ek carbon lambi hai, aur yeh lagbhag ek hi tarah react karte hain kyunki yeh –Cl group tay karta hai. Aisi family ek homologous series (समजातीय श्रेणी) hoti hai.

Definition

Homologous series

Same functional group wale carbon compounds ki family, jismein har member agle se ek $C H_{2}$ unit se alag hota hai.

ExampleAlkanes $C H_{4}$ , $C_{2} H_{6}$ , $C_{3} H_{8}$ …; alcohols $C H_{3} O H$ , $C_{2} H_{5} O H$ …

Series mein har step ek $C H_{2}$ unit jodta hai. C = 12 u aur H = 1 u lene par yeh $12 + 2 = 14$ u hai, isliye paas-paas ke members ka molecular mass hamesha 14 u se alag hota hai. Table 4.3 ke alkanes aisi hi series banate hain: $C H_{4}$ , $C_{2} H_{6}$ , $C_{3} H_{8}$ , $C_{4} H_{10}$ wagairah.

Atoms gino to ek pattern dikhta hai. $n$ carbon atoms wale alkane mein $2 n + 2$ hydrogen atoms hote hain. Ek double bond do hydrogens kam karta hai aur triple bond chaar, jisse Table 4.5 ke general formulas milte hain. Alkenes aur alkynes $n = 2$ se shuru hote hain, kyunki C=C ya C≡C bond ke liye do carbons chahiye.

Table 4.5Hydrocarbon series ke general formulas

Series	General formula	1st member	2nd	3rd
Alkanes	$C_{n} H_{2 n + 2}$	$C H_{4}$	$C_{2} H_{6}$	$C_{3} H_{8}$
Alkenes	$C_{n} H_{2 n}$	$C_{2} H_{4}$	$C_{3} H_{6}$	$C_{4} H_{8}$
Alkynes	$C_{n} H_{2 n - 2}$	$C_{2} H_{2}$	$C_{3} H_{4}$	$C_{4} H_{6}$

Fig. 4.8 mein alcohols dekho: har extra $C H_{2}$ molecule ko bhaari aur uska boiling point ooncha karta hai. Aisi series mein physical properties dheere-dheere badalti hain, har member par ek step. Solubility bhi badalti hai: teen sabse chhote alcohols paani mein kisi bhi amount mein mil jaate hain, jabki butanol sirf thoda ghulta hai. Chemical behaviour aise nahi badalta. Woh functional group se tay hota hai, isliye har member lagbhag ek hi tarah react karta hai.

3/3Boiling points lagaataar badhte hain: 65, 78, 97 aur 118 °C.

Fig. 4.8Har member

C H_{2}

(14 u) jodta hai; boiling point step by step badhta hai jabki chemistry same rehti hai.NCERT p. 67

Chaar columns mein methanol CH3OH 32 u, ethanol C2H5OH 46 u, propan-1-ol C3H7OH 60 u aur butan-1-ol C4H9OH 74 u dikhte hain. Step 1 mein sirf formulas aur masses hain. Step 2 mein paas-paas walon ke beech curved arrows judte hain, har ek par +CH2 aur +14 u likha hai. Step 3 mein boiling points ke bars judte hain, 65, 78, 97 aur 118 °C, jo left se right lagaataar badhte hain.

Example 4.2

Series ka ek member dhoondhna

Alkene series ke paanchve member ka formula likho. Uska molecular mass nikaalo, aur yeh bhi ki woh chauthe member se kitna bhaari hai (C = 12 u, H = 1 u).

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

Activity 4.2NCERT Activity 4.2 · p. 67

Acid family, ek-ek step karke

Tumhe chahiye

ek notebook
atomic masses: C = 12 u, H = 1 u, O = 16 u

Pehle guess karo

Tumhe kya lagta hai,

C H_{3} C O O H

aur

C_{2} H_{5} C O O H

mein kitne mass units ka fark hoga?

Pehle chaar carboxylic acids ke formulas likho: $H C O O H$ , $C H_{3} C O O H$ , $C_{2} H_{5} C O O H$ aur $C_{3} H_{7} C O O H$ .
Paas-paas ke har pair ke liye formula aur molecular mass ka fark nikaalo, aur table bharo.
Kya teeno pairs mein same fark hai? Kya yeh family ek homologous series hai?
Ab Table 4.4 ki do aur series ke pehle chaar members (chaar carbons tak) likho, jaise aldehydes aur chloroalkanes.

Table 4.6Paas-paas walon ke beech fark

Pair	Formula mein fark	Mass mein fark (u)
$H C O O H$ aur $C H_{3} C O O H$
$C H_{3} C O O H$ aur $C_{2} H_{5} C O O H$
$C_{2} H_{5} C O O H$ aur $C_{3} H_{7} C O O H$

Tumhari entries apne aap save hoti hain.

4.2.5 Carbon Compounds ki Nomenclature

Millions compounds ke saath chemists ko aise naam chahiye jo structure batayein. Poori duniya mein use hone wala system IUPAC, yaani International Union of Pure and Applied Chemistry, tay karta hai. Yeh naam do hisson se banata hai: ek stem jo carbon atoms ginta hai, aur ek prefix ya suffix jo functional group ka naam batata hai.

Chain mein carbon atoms gino, –CHO ya –COOH ke andar wala carbon bhi. Ginti se stem milta hai: 1 meth-, 2 eth-, 3 prop-, 4 but-, 5 pent-, 6 hex-. Sirf single bonds wale paanch carbons se pentane banta hai.
Group ka naam likho. Chlorine aur bromine prefix ki tarah likhe jaate hain (chloro-, bromo-); zyaadatar baaki groups suffix ki tarah (Table 4.7).
Vowel se pehle aakhri e hata do. Agar suffix vowel se shuru hota hai, to alkane ke naam ka -e hat jaata hai. Jaise pentane → pentan + -ol = pentanol; butane → butan + -one = butanone. Prefix se kuch nahi badalta: chlorobutane.
Unsaturation ending mein dikhao. C=C bond -ane ko -ene bana deta hai, aur C≡C bond -yne: butane, butene, butyne.

Table 4.7Prefixes aur suffixes

Class	Prefix ya suffix	Example
Haloalkane	prefix chloro-, bromo-	chloromethane, $C H_{3} C l$
Alcohol	suffix -ol	methanol, $C H_{3} O H$
Aldehyde	suffix -al	pentanal, $C_{4} H_{9} C H O$
Ketone	suffix -one	butanone, $C H_{3} C O C_{2} H_{5}$
Carboxylic acid	suffix -oic acid	butanoic acid, $C_{3} H_{7} C O O H$
Alkene	suffix -ene	propene, $C_{3} H_{6}$
Alkyne	suffix -yne	ethyne, $C_{2} H_{2}$

Example 4.3

Condensed formula se naam rakhna

In compounds ke naam batao: (a) $C H_{3} C H_{2} C H_{2} C H O$ (b) $C H_{3} C O C H_{2} C H_{3}$ (c) $C H_{3} C H_{2} C \equiv C H$ .

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

InteractiveCarbon compound builder

Ek interactive builder. Learner nau families mein se ek chunta hai (alkane, alkene, alkyne, chloroalkane, bromoalkane, alcohol, aldehyde, ketone, carboxylic acid) aur ek se chhe carbon atoms ki chain; jo choices exist nahi kar sakti, jaise ek-carbon alkene, woh grey ho jaati hain. Widget har atom aur bond ke saath poora structural formula banata hai, IUPAC naam deta hai, zaroorat ho to position number ke saath, aur koi common name ho to woh bhi, formula aur molecular mass, aur confirm karta hai ki har carbon ke chaar bonds hain. Ek strip chuni hui homologous series ke members unke masses ke saath dikhati hai, jo 14 u ke fark par hain. Quiz switch naam chhupa deta hai aur chunne ke liye teen naam deta hai.

Fig. 4.9Ek family aur chain length chuno aur poora structure, naam aur formula dekho. Pehle khud naam batane ke liye quiz on karo.

Quick check

4 mein se 1

Paanch carbons ki chain jiske end carbon par –OH group ho, uska naam hai.

Answer dekho

Answer pentanol

pent- + -ane → pentan + -ol = pentanol (poora naam pentan-1-ol).

Practice · 5 questions

Practice 4.2 (NCERT ke in-text questions, pp. 68–69): answers ke saath

1
Short answerHardNCERT in-text Q1, p. 68
Hexane, $C_{6} H_{14}$ , ke saare structural isomers ke condensed formulas likho. Kitne hain?
Solution dikhao
AnswerPaanch.
Paanch isomers hain:
$C H_{3} (C H_{2})_{4} C H_{3}$ , hexane
$(C H_{3})_{2} C H (C H_{2})_{2} C H_{3}$ , 2-methylpentane
$(C_{2} H_{5})_{2} C H C H_{3}$ , 3-methylpentane
$(C H_{3})_{2} C H C H (C H_{3})_{2}$ , 2,3-dimethylbutane
$(C H_{3})_{3} C C H_{2} C H_{3}$ , 2,2-dimethylbutane
Short answerEasyNCERT in-text Q2, p. 68
Ek classmate kehti hai ki carbon millions compounds "isliye banata hai kyunki woh non-metal hai". Use sudharo: carbon ki woh do properties batao jo asal mein iski wajah hain, aur batao ki har ek ka matlab kya hai.
Solution dikhao
AnswerCatenation aur tetravalency.
Catenation: carbon atoms ek doosre se lambi chains, branches aur rings mein bond banate hain. Tetravalency: har carbon chaar bonds banata hai, carbon se ya H, O, N, S aur Cl jaise atoms se. Dono milkar structures ki bahut badi variety possible banate hain. Non-metal hone ka isse koi lena-dena nahi; zyaadatar non-metals mein inmein se koi bhi property strong nahi hoti.
Short answerMediumNCERT in-text Q3, p. 68
Cyclobutane, yaani chaar carbon atoms ki ring, ka molecular formula likho aur uske electron-dot structure ko describe karo.
Solution dikhao
Answer $C_{4} H_{8}$ ; 12 shared pairs aur koi lone pair nahi.
Har carbon do valencies apne do carbon neighbours par use karta hai aur do hydrogen ke liye bachti hain: $4 \times 2 = 8$ H, isliye formula hai $C_{4} H_{8}$ .
Dot structure mein har carbon har padosi carbon ke saath ek pair share karta hai aur apne do hydrogens mein se har ek ke saath ek. Isse 4 C–C pairs + 8 C–H pairs = 12 shared pairs bante hain, aur har carbon ka octet poora hota hai.
4
DiagramMediumNCERT in-text Q4, p. 69
Har compound ka condensed structural formula likho.
1. propanoic acid
  Solution dikhao
  Teen carbons, aakhri wala –COOH mein: $C H_{3} C H_{2} C O O H$ .
2. chlorobutane. Kya isomers possible hain?
  Solution dikhao
  $C H_{3} C H_{2} C H_{2} C H_{2} C l$ (1-chlorobutane). Haan: Cl doosre carbon par bhi ho sakta hai, $C H_{3} C H_{2} C H C l C H_{3}$ , aur chain khud bhi branch ho sakti hai, isliye kul chaar isomers hain.
3. pentanal
  Solution dikhao
  $C H_{3} (C H_{2})_{3} C H O$ : paanch carbons, –CHO wale carbon ko milakar.
4. pentanone. Do answers kyun possible hain?
  Solution dikhao
  C=O carbon 2 par ho sakta hai, $C H_{3} C O C_{3} H_{7}$ (pentan-2-one), ya carbon 3 par, $C_{2} H_{5} C O C_{2} H_{5}$ (pentan-3-one). Yeh end par nahi ho sakta, warna aldehyde ban jaayega.
5
Short answerEasyNCERT in-text Q5, p. 69
In compounds ke naam batao.
1. $C H_{3} C H_{2} C H_{2} C l$
  Solution dikhao
  Chloropropane (1-chloropropane): teen carbons, end par Cl.
2. $C H_{3} C H O$
  Solution dikhao
  Ethanal: do carbons, ek aldehyde.
3. $C H_{3} C H_{2} C H_{2} C \equiv C H$
  Solution dikhao
  Pentyne (pent-1-yne): paanch carbons, ek triple bond.
4. $H C O O H$
  Solution dikhao
  Methanoic acid: ek carbon, –COOH group mein.

4.3 Carbon Compounds ki Chemical Properties

Gas stove jalao, scooter start karo ya thermal power station chalao, aur tum carbon compounds ki sabse important reaction use kar rahe ho: jalna. Hum wahin se shuru karte hain, aur phir teen naram tarah ki reactions se milte hain.

4.3.1 Combustion

Kaafi garam aag mein diamond, graphite aur charcoal sabka ek hi anjaam hota hai: woh carbon dioxide ban jaate hain. Carbon compounds bhi jalte hain, aur unmein jo bhi hydrogen ho woh paani ban kar nikalta hai. Inmein se har ek oxidation (Chapter 1) hai jo bahut saari heat aur light deta hai.

Carbon jalta hai

C + O_{2} \overset{}{\to} C O_{2}

(4.1)

Methane (CNG) jalti hai

\begin{aligned} C H_{4} + 2 O_{2} \\ \overset{}{\to} C O_{2} + 2 H_{2} O \end{aligned}

(4.2)

Ethanol jalta hai

\begin{aligned} C_{2} H_{5} O H + 3 O_{2} \\ \overset{}{\to} 2 C O_{2} + 3 H_{2} O \end{aligned}

(4.3)

Har side par C, H aur O atoms gin kar check karo ki aakhri do equations balanced hain.

Example 4.4

LPG ke jalne ko balance karna

Cooking gas zyaadatar butane, $C_{4} H_{10}$ , hai. Iske complete combustion ki balanced equation likho.

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

Activity 4.3NCERT Activity 4.3 · p. 69

Kaunsi flames soot chhodti hain?

Tumhe chahiye

ek camphor tablet (kapoor)
naphthalene ke kuch flakes (mothball se)
china dish mein ethanol ki kuch boondein
candle wax ka ek chhota tukda
ek steel plate ya dhakkan, chimta aur maachis

Pehle guess karo

Tumhe kya lagta hai, inmein se kaunsa sabse saaf flame ke saath jalega?

camphornaphthaleneethanol

Apne teacher ke saath, har substance ki thodi si quantity ek-ek karke spatula par ya dish mein jalao.
Har flame ka colour note karo aur yeh bhi ki usse dhuan uthta hai ya nahi.
Steel plate ko chimte se pakad kar har flame ke thoda upar kuch seconds rakho aur dekho ki kaala deposit jamta hai ya nahi.

Table 4.8Har flame ne kya kiya

Substance	Flame ka colour	Dhuan?	Plate par soot?
Camphor
Naphthalene
Ethanol
Candle wax

Tumhari entries apne aap save hoti hain.

Activity 4.4NCERT Activity 4.4 · p. 69

Blue flame ya yellow?

Tumhe chahiye

gas supply se juda ek Bunsen burner
chimte mein pakdi ek steel plate

Pehle guess karo

Tum burner ke base par air hole band kar dete ho. Flame ka kya hota hai?

Woh yellow aur dhuen wali ho jaati haiWoh blue aur shaant ho jaati haiWoh turant bujh jaati hai

Air hole poora khol kar burner jalao aur flame dekho.
Dheere-dheere collar ghuma kar air hole band karo aur flame ko badalte dekho.
Har tarah ki flame ke upar steel plate thodi der rakho aur plate compare karo.

2/2Bahut kam hawa: incomplete combustion, yellow flame aur soot.

Fig. 4.10Kaafi hawa se blue, saaf flame milti hai; bahut kam hawa se yellow, soot wali.NCERT Activity 4.4 · p. 69

Steel plate ke neeche ek Bunsen burner. Step 1: air hole khula hai, ek arrow hawa ko andar jaate dikhata hai; flame ek chhota blue cone hai aur plate saaf rehti hai; labels batate hain ki gas poori tarah jalti hai. Step 2: air hole dhaka hai aur us par cross laga hai; flame lambi, yellow aur lehraati hai, usse soot particles uthte hain aur plate ke neeche ek kaala dhabba banta hai; labels batate hain ki gas adhoori jalti hai.

Flame kitni saaf hogi, yeh do cheezein tay karti hain. Ek hai fuel. Methane jaise saturated hydrocarbon mein har carbon ke liye bahut hydrogen hota hai aur woh aksar blue jalta hai, jabki ethyne ya naphthalene jaise unsaturated, carbon se bhare fuels yellow aur dhuen ke saath jalte hain. Doosri hai hawa: methane ko bhi oxygen kam do to uska kuch carbon soot ban kar nikal jaata hai. Kitchen burner isi baat ko dhyaan mein rakh kar banaya jaata hai: woh base ke paas ke holes se hawa kheenchta hai aur jalne se pehle use gas ke saath milata hai. Jab yeh holes gire hue khaane se band ho jaate hain, to flame yellow ho jaati hai, soot patila ke tale ko kaala kar deta hai, aur tum us gas ke paise dete ho jo tumhara khana nahi paka rahi.

Fossil fuels pure carbon compounds nahi hain. Coal aur petroleum mein thoda sulphur aur nitrogen hota hai, jo chimney ya exhaust pipe se sulphur dioxide aur nitrogen oxides ban kar nikalte hain. Yeh gases humare lungs ko irritate karti hain aur baarish mein ghul kar use acidic bana deti hain.

Kya aap jaante hain?NCERT Kya Tum Jaante Ho? · p. 70

Flames, chamak aur colours

Candle ki flame yellow kyun hoti hai jabki gas burner ki flame blue? Candle apne wax vapour tak kaafi hawa nahi pahuncha paati, isliye flame mein bina jale carbon ke chhote-chhote kan bante hain. White-hot hone tak garam hokar woh yellow chamakte hain; flame mein ek thandi chammach rakho to woh soot ban kar jam jaate hain. Sadak kinare bhutta bechne wale ki coal ki angeethi bhi dekho. Pehli flames shaant hone ke baad koyle laal chamakte hain lekin koi flame nahi dikhti. Flame ke liye ek jalti hui gas chahiye: naya coal ya lakdi vapours chhodte hain jo flames ban kar jalte hain, jabki bacha hua solid sirf chamak sakta hai. Alag elements ke garam particles alag colours mein chamakte hain: gas flame par chutki bhar namak chhidko to woh tez yellow chamakta hai, jo sodium ka colour hai.

4.3.2 Oxidation

Activity 4.5NCERT Activity 4.5 · p. 70

Purple colour ko gayab hote dekho

Tumhe chahiye

test tube mein lagbhag 2 mL ethanol
garam paani ka ek beaker (water bath)
5 % alkaline potassium permanganate solution
ek dropper

Pehle guess karo

Tum garam ethanol mein purple potassium permanganate boond-boond daalte ho. Pehli kuch boondon ka kya hota hai?

Purple colour gayab ho jaata haiPurple colour bana rehta haiMixture green ho jaata hai aur ubalne lagta hai

Ethanol wali test tube ko ek minute garam paani mein khada rakho. Ethanol ko kabhi flame par garam mat karo.
Permanganate solution ek-ek boond karke daalo, har boond ke baad halka sa hilao.
Dekho pehli kuch boondon ke colour ka kya hota hai, phir tab tak daalte raho jab tak colour jaana band na ho jaaye.

2/3Har boond ethanol ko oxidise karne mein use ho jaati hai.

Fig. 4.11Jab tak ethanol bacha hai, har boond use hoti hai; saara oxidise hone ke baad purple bana rehta hai.NCERT Activity 4.5 · p. 70

Ethanol ki ek test tube garam paani ke beaker mein khadi hai, aur uske upar purple potassium permanganate ka dropper hai. Step 1: ethanol colourless hai aur dropper se ek purple boond latki hai. Step 2: boond andar girti hai aur uska colour gayab ho jaata hai, kyunki woh ethanol ko ethanoic acid mein oxidise karne mein use ho jaati hai. Step 3: kai boondon ke baad liquid purple hi rehta hai, kyunki oxidise karne ko koi ethanol nahi bacha.

Jalna poori tarah ki oxidation hai: har carbon aakhir mein carbon dioxide ban jaata hai. Halki oxidation beech raaste ruk sakti hai. Ethanol ko alkaline potassium permanganate, $K M n O_{4}$ , ya acidified potassium dichromate, $K_{2} C r_{2} O_{7}$ , ke saath garam karo. –OH wala end carbon –COOH group ban jaata hai, aur alcohol utne hi carbons wale carboxylic acid mein badal jaata hai:

Ethanol se ethanoic acid

\begin{aligned} C H_{3} C H_{2} O H \\ \to_{h e a t}^{K M n O_{4}} C H_{3} C O O H \end{aligned}

(4.4)

Aise substances, jo kisi doosre substance ko oxygen dete hain, oxidising agents kehlaate hain. Isi badlaav ka dheema version humein vinegar deta hai: bacteria fermented ganne ke ras ya fruit juice ke ethanol ko ethanoic acid mein oxidise kar dete hain.

Definition

Oxidising agent

Woh substance jo kisi doosre substance ko oxygen deta hai, yaani use oxidise karta hai.

ExampleAlkaline $K M n O_{4}$ aur acidified $K_{2} C r_{2} O_{7}$ ethanol ko ethanoic acid mein oxidise karte hain.

4.3.3 Addition Reaction

Double ya triple bond ek kamzor jagah hai jahan naye atoms jud sakte hain. Hydrogen aur ethene ko bareek pise nickel ya palladium ke upar se guzaaro, aur har carbon ek aur hydrogen atom le leta hai, jisse saturated ethane banta hai. Metal ek catalyst hai: yeh reaction ko normal temperature par tezi se chalne deta hai aur reaction khatam hone par bhi bina badle wahin rehta hai. Kyunki do molecules milkar ek banate hain, yeh ek addition reaction hai.

Ethene se ethane

\begin{aligned} C H_{2} = C H_{2} + H_{2} \\ \to_{h e a t}^{N i} C H_{3} - C H_{3} \end{aligned}

(4.5)

Definition

Addition reaction

Aisi reaction jismein atoms double ya triple bond par judte hain, aur unsaturated compound saturated ban jaata hai.

ExampleNickel catalyst ke saath oil ka hydrogenation.

Industry is reaction se vegetable oils ko hydrogenate karti hai. Moongphali, sarson ya sunflower jaise oils mein kai double bonds wali lambi carbon chains hoti hain, aur woh liquid hote hain. Bareek pise nickel wale garam oil mein se hydrogen ke bubbles guzaarne par inmein se kai bonds saturated ho jaate hain. Seedhi, saturated chains aasaani se paas-paas jam jaati hain, aur oil ek soft solid fat, vanaspati ghee, ban jaata hai.

3/3Har carbon par ek H judta hai aur double bond single ban jaata hai.

Fig. 4.12Nickel catalyst par

H_{2}

C=C bond par judta hai aur oil saturated fat ban jaata hai.NCERT p. 71

Oil molecule ka ek hissa: ek line mein chaar carbon atoms unke hydrogens ke saath, beech wale do double bond se jude. Step 1: chain ke neeche ek hydrogen molecule, H–H, hai; labels par likha hai vegetable oil, C=C, unsaturated. Step 2: hydrogen ke neeche nickel surface aati hai aur H–H bond toot jaata hai. Step 3: beech ke dono carbons mein se har ek par ek hydrogen atom judta hai, double bond single ban jaata hai, aur label par likha hai vanaspati ghee, saturated chain.

Cooking-oil ki bottles ke labels aksar "PUFA" aur "MUFA" ka dum bharte hain, yaani vegetable oils ke poly- aur mono-unsaturated fatty acids. Iske ulat, butter, ghee aur vanaspati zyaadatar saturated hote hain. Bahut zyaada saturated fat khaane ka sambandh heart disease se hai, isiliye doctors zyaadatar unsaturated oils mein khana pakaane ki salaah dete hain.

4.3.4 Substitution Reaction

Alkane mein kholne ke liye koi double bond nahi hota, isliye naye atoms ke judne ki koi jagah nahi, aur zyaadatar reagents use chhod hi dete hain. Sunlight mein chlorine ek exception hai. Methane aur chlorine ke mixture par roshni daalo to woh tezi se react karte hain: ek chlorine atom ek hydrogen atom ko bahar dhakel kar uski seat le leta hai, aur hydrogen, hydrogen chloride ban kar nikal jaata hai. Kyunki ek atom doosre ki jagah leta hai, ise substitution reaction kehte hain.

Methane aur chlorine

\begin{aligned} C H_{4} + C l_{2} \\ \overset{s u n l i g h t}{\to} C H_{3} C l + H C l \end{aligned}

(4.6)

Zyaada chlorine ke saath yeh adla-badli chalti rehti hai, aur $C H_{2} C l_{2}$ , $C H C l_{3}$ (chloroform) aur $C C l_{4}$ bante hain, har step par ek $H C l$ nikalta hai. Lambe alkanes mein badle ja sakne wale bahut hydrogens hote hain, isliye unse aksar products ka mixture milta hai.

2/5Ek H badla: chloromethane, $C H_{3} C l$ .

Fig. 4.13Sunlight mein Cl ek-ek atom karke H ki jagah leta hai, aur har swap HCl chhodta hai.NCERT p. 71

Methane molecule ko chaar hydrogen atoms se bonded ek carbon atom ki tarah banaya gaya hai, aur kone mein ek suraj hai. Step 1: methane, CH4. Step 2: right wala hydrogen chlorine atom se badalta hai, jisse chloromethane, CH3Cl, aur ek HCl banta hai. Step 3: upar wala hydrogen bhi badalta hai, jisse dichloromethane, CH2Cl2, banta hai. Step 4: left wala hydrogen badalta hai, jisse trichloromethane (chloroform), CHCl3, banta hai. Step 5: chaaron chlorine hain, tetrachloromethane, CCl4, aur chaar HCl ban chuke hain.

Definition

Substitution reaction

Aisi reaction jismein molecule ka koi atom ya group kisi doosre atom ya group se badal jaata hai.

ExampleSunlight mein $C H_{4} + C l_{2} \overset{}{\to} C H_{3} C l + H C l$ .

Practice · 2 questions

Practice 4.3 (NCERT ke in-text questions, p. 71): answers ke saath

Short answerMediumNCERT in-text Q1, p. 71
Lab mein propan-1-ol ko acidified potassium dichromate ke saath garam kiya jaata hai aur woh propanoic acid ban jaata hai. Is badlaav ko oxidation kyun kehte hain?
Solution dikhao
AnswerCompound ko oxygen milti hai (aur hydrogen kam hota hai).
Propan-1-ol $C_{3} H_{8} O$ hai aur propanoic acid $C_{3} H_{6} O_{2}$ . Product mein ek oxygen atom zyaada aur do hydrogen atoms kam hain. Oxygen milna (ya hydrogen khona) oxidation hai, aur dichromate woh oxidising agent hai jo oxygen deta hai.
Short answerMediumNCERT in-text Q2, p. 71
Glass-blower ki torch LPG ko hawa ki jagah pure oxygen ke saath milakar jalaati hai. Kyun?
Solution dikhao
AnswerPure oxygen fuel ko poori tarah aur kahin zyaada garam jalaati hai.
Hawa mein lagbhag 78 % nitrogen hai, jo jalne mein koi hissa nahi leta lekin heat sokh leta hai, aur hawa oxygen bhi dheere-dheere hi deti hai. Pure oxygen ke saath fuel poori tarah aur tezi se jalta hai, isliye flame saaf aur bahut zyaada garam hoti hai, itni ki glass naram ho jaaye. Gas welders isi wajah se ethyne ko oxygen ke saath milate hain.

4.4 Kuch Important Carbon Compounds – Ethanol aur Ethanoic Acid

Do carbon compounds ko kareeb se dekhna chahiye kyunki hum unhe bahut badi quantity mein banate aur use karte hain: ethanol aur ethanoic acid. Inmein sirf ek group ka fark hai, phir bhi yeh bilkul alag tarah behave karte hain.

4.4.1 Ethanol ki Properties

Hand sanitiser ka label padho: uska main ingredient aksar ethanol, $C_{2} H_{5} O H$ , hota hai, lagbhag 70 %. Ethanol, jise aksar sirf alcohol kehte hain, ek colourless liquid hai jo 78 °C par ubalta hai (Table 4.2), isliye yeh tumhare haathon se jaldi udd jaata hai. Yeh paani mein kisi bhi ratio mein mil jaata hai, aur kai aise substances ghol leta hai jo paani nahi ghol sakta: jaise tincture of iodine, ethanol mein ghula iodine hai.

Ethanol alcoholic drinks mein nasha karne wala substance bhi hai, aur yeh ek zeher hai. Thoda sa bhi soch-samajh ko kamzor karta hai aur insaan ko nashe mein kar deta hai. Pure liquid (absolute alcohol) peena jaan le sakta hai, aur saalon tak peene se liver aur doosre organs kharaab ho jaate hain.

(i) Sodium ke saath reaction. Ethanol mein sodium daalo to woh fizz karta hai, bilkul waise jaise reactive metals paani ya acids mein karte hain. Gas hydrogen hai, aur sodium aakhir mein sodium ethoxide mein chala jaata hai, jo ek ionic compound hai.

Sodium ethoxide banta hai

\begin{aligned} 2 N a + 2 C H_{3} C H_{2} O H \\ \overset{}{\to} 2 C H_{3} C H_{2} O^{-} N a^{+} \\ + H_{2} \end{aligned}

(4.7)

(ii) Paani hataana: ethene banana. Concentrated sulphuric acid ko paani ki bahut pyaas hoti hai. Ethanol ko iski zyaada quantity ke saath 443 K (170 °C) tak garam karo, aur acid ek carbon se H aur doosre se OH kheench leta hai, aur ethene bachta hai. Jo substance is tarah compound se paani nikaal leta hai, use dehydrating agent kehte hain.

Ethanol ka dehydration

\begin{aligned} C H_{3} C H_{2} O H \\ \to_{443 K}^{H_{2} S O_{4}} C H_{2} = C H_{2} \\ + H_{2} O \end{aligned}

(4.8)

Kya aap jaante hain?NCERT Kya Tum Jaante Ho? · p. 72

Alcohol shareer ke saath kya karta hai

Methanol, ethanol ka ek-carbon wala cousin, kahin zyaada khatarnak hai. Kuch chammach bhi andha kar sakte hain ya jaan le sakte hain: liver methanol ko methanal mein badal deta hai, jo cells ke proteins ko barbaad kar deta hai, aur optic nerve khaas taur par aasaani se damage hoti hai. India mein illicit liquor (hooch) se hone wali kai maut methanol ki wajah se hoti hain. Factories bahut saara ethanol solvent ki tarah use karti hain, isliye use peene se rokne ke liye usmein zehreela methanol milakar blue rang diya jaata hai. Yeh denatured alcohol, ya methylated spirit, sasta hai aur peene layak nahi. Khud ethanol bhi zyaada peene par brain aur nerves ko dheema kar deta hai: peene wale ko pata chalne se pehle hi reactions, balance aur soch-samajh bigad jaate hain, aur bahut zyaada peene ka ant confusion, neend aur gir padne mein hota hai.

4.4.2 Ethanoic Acid ki Properties

Pyaaz ke achaar ke jar mein sirka ka khatta swaad ethanoic acid, $C H_{3} C O O H$ , se aata hai, jise acetic acid bhi kehte hain. Kitchen ka vinegar bas paani mein 5–8 % ethanoic acid hai. Pure acid bilkul alag hai: yeh corrosive hai, aur 290 K (17 °C) par jam jaata hai, isliye thandi lab mein yeh barf jaise crystals ban jaata hai. Isiliye ise glacial acetic acid ke naam se becha jaata hai. Ethanoic acid carboxylic acids mein aata hai, jo –COOH group wali family hai.

Paani mein ethanoic acid ke molecules ka sirf chhota sa hissa $H^{+}$ ions chhodta hai, jabki hydrochloric acid ka har molecule chhodta hai. Isliye same strength par ethanoic acid kahin kam $H^{+}$ ions deta hai: yeh ek weak acid hai, aur hydrochloric acid ek strong acid.

Activity 4.7NCERT Activity 4.7 · p. 73

Same strength, alag acidity

Tumhe chahiye

same strength ka dilute hydrochloric acid aur dilute ethanoic acid
kitchen ka white vinegar
blue litmus paper
universal indicator paper aur uska colour chart

Pehle guess karo

Dono acids barabar dilute hain. Unki pH values ka comparison kaisa hoga?

Dono ka pH same hogaEthanoic acid ka pH kam hogaHydrochloric acid ka pH kam hoga

Har sample ki ek boond blue litmus paper par daalo.
Har ek ki ek boond universal indicator paper par daalo aur chart se pH padho.

Table 4.9Acids ka comparison

Sample	Blue litmus	Indicator ka colour	pH
Dilute hydrochloric acid
Dilute ethanoic acid
Vinegar

Tumhari entries apne aap save hoti hain.

(i) Esterification. Mithai mein pineapple, kele ya aam ka flavour aksar bageeche mein nahi, factory mein banta hai: yeh ek ester hai. Ester tab banta hai jab ek carboxylic acid aur ek alcohol judte hain, thode se concentrated sulphuric acid ki madad se, aur doosra product paani hota hai. Esters ki smell meethi ya fruity hoti hai, isliye inhe perfumes aur flavourings mein use kiya jaata hai.

Activity 4.8NCERT Activity 4.8 · p. 73

Fruity smell banao

Tumhe chahiye

2 mL absolute ethanol
2 mL glacial ethanoic acid
concentrated sulphuric acid ki 4 ya 5 boondein
ek test tube, garam paani ka ek beaker aur thande paani ka ek beaker

Pehle guess karo

Product se tumhe kis tarah ki smell expected hai?

tez, vinegar jaisifruity aur meethikoi smell nahi

Test tube mein ethanol aur glacial ethanoic acid milao; concentrated sulphuric acid ki boondein tumhare teacher daalte hain.
Tube ko garam paani ke bath mein lagbhag das minute khada rakho.
Mixture ko thande paani mein daalo. Seedhe mat soongho: uske upar ki hawa ko haath se apni naak ki taraf lehraao.

3/3Bache hue do tukde bond karte hain: ethyl ethanoate, ek ester.

Fig. 4.14Acid –OH khota hai aur alcohol H; inse paani banta hai, aur baaki hisse judkar ester banate hain.NCERT Activity 4.8 · p. 73

Step 1: ethanoic acid, CH3–C(=O)–O–H, aur ethanol, H–O–CH2CH3, aamne-saamne; acid ka O–H aur alcohol ka H gol ghere mein hain. Step 2: yeh atoms saath mein door jaate hain aur ek water molecule, H–O–H, banate hain. Step 3: alcohol ka oxygen acid ke carbon se judta hai, aur ester ethyl ethanoate, CH3–C(=O)–O–CH2CH3, banta hai, jiski smell fruity hai.

Esterification

\begin{aligned} C H_{3} C O O H \\ + C_{2} H_{5} O H \\ \overset{a c i d}{\to} C H_{3} C O O C_{2} H_{5} \\ + H_{2} O \end{aligned}

(4.9)

Definition

Esterification

Acid catalyst ke saath carboxylic acid aur alcohol ki reaction, jisse ester aur paani bante hain.

ExampleEthanoic acid + ethanol → ethyl ethanoate + paani.

Esters ko phir se toda ja sakta hai. Ester ko sodium hydroxide solution ke saath ubaalo to alcohol wapas mil jaata hai, lekin acid apne sodium salt ke roop mein nikalta hai. Oils aur fats mein milne wale long-chain esters ke saath yeh sodium salt soap hota hai, isliye is reaction ka naam saponification hai (Latin sapo, soap). Yaani soaps lambi carbon chains wale carboxylic acids ke sodium ya potassium salts hain.

Saponification

\begin{aligned} C H_{3} C O O C_{2} H_{5} \\ + N a O H \\ \overset{}{\to} C_{2} H_{5} O H \\ + C H_{3} C O O N a \end{aligned}

(4.10)

(ii) Base ke saath reaction. Ethanoic acid sodium hydroxide ko waise hi neutralise karta hai jaise hydrochloric acid karta. Banne wala salt sodium ethanoate hai, jise sodium acetate ke naam se zyaada jaana jaata hai, aur doosra product paani hai.

Neutralisation

\begin{aligned} C H_{3} C O O H + N a O H \\ \overset{}{\to} C H_{3} C O O N a \\ + H_{2} O \end{aligned}

(4.11)

(iii) Washing soda aur baking soda. Carbonate ya hydrogencarbonate mein ethanoic acid daalo to fizz hota hai: ek salt, paani aur carbon dioxide bante hain. Activity 4.9 mein try karo.

Activity 4.9NCERT Activity 4.9 · p. 74

Washing soda aur baking soda se fizz

Tumhe chahiye

ek spatula washing soda (sodium carbonate)
ek spatula baking soda (sodium hydrogencarbonate)
dilute ethanoic acid ya white vinegar
cork aur delivery tube wali ek test tube
taaza bana lime water

Pehle guess karo

Is reaction ki gas lime water ke saath kya karegi?

Kuch nahiUse blue kar degiUse milky kar degi

Test tube aur delivery tube waise hi set karo jaise Chapter 2 (Activity 2.5) mein acids aur carbonates ke liye kiya tha.
Tube mein washing soda daalo, lagbhag 2 mL dilute ethanoic acid milao aur jaldi se cork laga do.
Gas ko lime water mein se bubble karo aur dekho.
Baking soda ke saath dohrao.

Sodium carbonate ke saath

\begin{aligned} 2 C H_{3} C O O H \\ + N a_{2} C O_{3} \\ \overset{}{\to} 2 C H_{3} C O O N a \\ + H_{2} O + C O_{2} \end{aligned}

(4.12)

Sodium hydrogencarbonate ke saath

\begin{aligned} C H_{3} C O O H \\ + N a H C O_{3} \\ \overset{}{\to} C H_{3} C O O N a \\ + H_{2} O + C O_{2} \end{aligned}

(4.13)

Compare

Ethanol aur ethanoic acid mein fark kaise pehchanein

Ethanol

78 °C par ubalta hai, −114 °C par jamta hai
Halki, spirit jaisi smell
Blue litmus par koi asar nahi
Baking soda ke saath koi reaction nahi
Sodium ke saath $H_{2}$ deta hai

Ethanoic acid

118 °C par ubalta hai, 17 °C par jamta hai
Vinegar ki tez smell
Blue litmus ko red karta hai
Baking soda ke saath fizz karta hai, $C O_{2}$ deta hai
Sodium ke saath yeh bhi $H_{2}$ deta hai

Example 4.5

Compounds pehchano

Ek neutral liquid A, $C_{2} H_{6} O$ , mein sodium daalne par ek gas nikalti hai jo pop ki awaaz ke saath jalti hai. Alkaline potassium permanganate ke saath garam karne par A se B milta hai, jo baking soda ke saath fizz karta hai. A aur B ko concentrated sulphuric acid ki kuch boondon ke saath garam karne par C milta hai, jiski smell fruity hai. A, B aur C pehchano aur C banne ki equation likho.

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

Practice · 2 questions

Practice 4.4 (NCERT ke in-text questions, p. 74): answers ke saath

Short answerEasyNCERT in-text Q1, p. 74
Do bina label wali bottles mein propan-1-ol aur propanoic acid hain. Ek chemical test batao jo inmein fark kare, aur tumhe kya dikhega.
Solution dikhao
AnswerSodium hydrogencarbonate daalo: sirf acid fizz karta hai.
Dono ki thodi-thodi quantity mein ek chutki sodium hydrogencarbonate (ya sodium carbonate) daalo. Propanoic acid fizz karta hai aur carbon dioxide deta hai, jo lime water ko milky kar deti hai; propan-1-ol mein koi badlaav nahi hota. Blue litmus bhi kaam karta hai: sirf acid use red karta hai.
Short answerEasyNCERT in-text Q2, p. 74
Oxidising agent kya karta hai? Do oxidising agents ke naam batao jo ethanol ko ethanoic acid mein badalte hain.
Solution dikhao
AnswerYeh oxygen deta hai; alkaline $K M n O_{4}$ aur acidified $K_{2} C r_{2} O_{7}$ .
Oxidising agent kisi doosre substance ko oxygen deta hai (ya usse hydrogen hataata hai), aur is tarah use oxidise karta hai. Alkaline potassium permanganate aur acidified potassium dichromate dono ethanol ke saath garam karne par use ethanoic acid mein oxidise kar dete hain.

4.5 Soaps aur Detergents

Chiknai wali plate ko sirf paani se dho, to chiknai wahin rehti hai; thoda soap daalo to woh utar jaati hai. Soap woh kyun kar paata hai jo paani nahi kar paata? Ek simple test se shuru karo.

Activity 4.10NCERT Activity 4.10 · p. 74

Kya soap oil aur paani ko mila kar rakh sakta hai?

Tumhe chahiye

cap wali do chhoti transparent bottles, jin par P aur Q likha ho
paani
do chammach sarson ka tel
liquid soap ya soap solution

Pehle guess karo

Hilaane ke baad kis bottle mein oil ko alag hone mein zyaada time lagega?

P, sirf oil aur paaniQ, jismein soap daala gayaDono mein barabar

Dono bottles aadhi paani se bharo aur har ek mein ek chammach oil daalo.
Sirf bottle Q mein soap solution ki kuch boondein daalo.
Dono ki cap lagao aur dono ko barabar zor se, utne hi time tak hilao.
Rukte hi unhe dekho, aur paanch minute baad phir dekho. Oil ki saaf layer pehle kahan dikhti hai?

Sirf paani chiknai wale collar ko saaf nahi kar sakta, kyunki chiknai aur paani milte hi nahi, aur zyaadatar gandagi kapde par chiknai ki ek parat ke zariye chipki hoti hai. Soap beech ke middleman ki tarah kaam karta hai. Har soap molecule ka shape tadpole jaisa hota hai. Iska head ionic hai, ek $C O O^{-}$ group sodium ya potassium ion ke saath, aur paani ki taraf kheencha jaata hai: yeh hydrophilic hai. Iski lambi tail ek hydrocarbon chain hai jo oil mein mil jaati hai lekin paani se door bhaagti hai: yeh hydrophobic hai.

Chiknai ke daag par saabun wala paani daalo to chains chiknai mein ghus jaati hain jabki ionic heads paani mein rehte hain. Molecules oily boond ke chaaron taraf jama ho jaate hain, heads bahar ki taraf, ek ball mein jise micelle kehte hain. Ragadne aur khangaalne se micelles, andar fasi chiknai ke saath, kapde se utar kar beh jaate hain.

3/4Chiknai soap molecules ki ek ball ke andar utha li jaati hai.

Fig. 4.15Tails chiknai ko pakadti hain, heads paani mein rehte hain, aur micelle chiknai ko le jaata hai.NCERT Figs 4.12–4.13 · p. 75

Step 1: ek soap molecule, oil pasand karne wali lambi zigzag carbon tail aur paani pasand karne wala gol ionic head, jis par minus sign aur ek sodium ion bana hai. Step 2: paani mein kapde ke fibre par chiknai ki ek boond hai aur soap molecules apni tails usmein ghusaate hain, heads paani mein. Step 3: chaaron taraf se ghirkar boond fibre se micelle ban kar uth jaati hai, tails andar aur heads paani ki taraf. Step 4: khangaalne ka paani micelle ko baha le jaata hai; micelles ek doosre ko repel karte hain kyunki unke heads par same charge hai.

Definition

Micelle

Paani mein soap molecules ka ek jhund, jismein hydrocarbon tails andar ki taraf hoti hain, aksar oily gandagi ke aas-paas, aur ionic heads paani ki taraf.

Ab dekho jab paani hard ho to kya hota hai.

Activity 4.11NCERT Activity 4.11 · p. 76

Soft water aur hard water

Tumhe chahiye

do test tubes
10 mL distilled water ya baarish ka paani
hand-pump ya tube well ka 10 mL hard water
soap solution aur ek dropper
ek ruler

Pehle guess karo

Tumhe kis tube mein zyaada jhaag expected hai?

distilled waterhard waterdono mein barabar

Ek tube mein distilled water aur doosri mein hard water daalo.
Har ek mein soap solution ki teen boondein daalo.
Dono ko barabar zor se, utne hi time tak hilao aur jhaag ki height naapo.
Dekho kisi tube mein safed, dahi jaisa solid hai ya nahi.

Teacher ke liye note: agar paas mein hard water nahi hai, to tap water mein ek chutki calcium chloride ya magnesium sulphate (Epsom salt) ghol lo.

Table 4.10Jhaag aur scum

Paani	Jhaag ki height (cm)	Safed dahi jaisa solid?
Distilled water
Hard water

Tumhari entries apne aap save hoti hain.

2/3Calcium aur magnesium ions soap ko insoluble scum bana dete hain.

Fig. 4.16Hard water ke calcium ions soap ko scum bana dete hain; detergents par asar nahi hota.NCERT Activities 4.11–4.12 · p. 76

Paani ki ek test tube, uske paas labels. Step 1: soft water mein soap, jhaag ka ooncha column aur koi scum nahi. Step 2: hard water mein soap, sirf teen bubbles aur paani mein scum ke safed dahi jaise kan, saath mein equation 2RCOO− + Ca2+ → (RCOO)2Ca, ek insoluble solid, jahan R ek lambi carbon chain hai. Step 3: hard water mein detergent, phir se ooncha jhaag aur koi scum nahi, kyunki detergent ka calcium salt ghula rehta hai.

Jo shehar borewells par nirbhar hain, wahan nahaane ki balti mein aksar ek grey, chipchipa ghera ban jaata hai, aur soap jhaag banane se pehle hi gayab sa ho jaata hai. Borewell ka paani aksar hard hota hai: usmein ghule hue calcium aur magnesium ions hote hain. Yeh ions soap ke saath react karke insoluble salts, yaani scum, banate hain, aur uske baad bacha hua soap hi jhaag bana paata hai.

Scum banta hai

\begin{aligned} 2 R C O O^{-} + C a^{2 +} \\ \overset{}{\to} (R C O O)_{2} C a ↓ \end{aligned}

(4.14)

jahan

$R$: ek lambi hydrocarbon chain, jaise sodium stearate mein $C_{17} H_{35}$

Detergents is problem ka hal nikaalte hain. Detergent molecule mein bhi lambi hydrocarbon tail aur charged head hota hai, isliye yeh bhi soap ki tarah micelles ke zariye saaf karta hai. Fark head mein hai: zyaadatar detergents sulphonic acids ke sodium salts hain, aur kuch chloride ya bromide ions wale ammonium salts hain. Calcium aur magnesium in heads ko solution se bahar nahi kheench paate, isliye scum nahi banta aur detergent hard water mein kaam karta rehta hai. Isiliye washing powders, shampoos aur dish-wash liquids zyaadatar detergents hote hain.

Compare

Soap aur detergent

Soap

Long-chain carboxylic acid ka sodium ya potassium salt
Vegetable oils ya animal fats se banta hai
Hard water mein scum banata hai
Nahaane ka soap aur kapde dhone ki bars

Detergent

Aam taur par long-chain sulphonic acid ka sodium salt
Zyaadatar petroleum chemicals se banta hai
Hard water mein kaam karta hai: koi scum nahi
Shampoos, washing powders, dish-wash liquids

Practice · 2 questions

Practice 4.5 (NCERT ke in-text questions, p. 76): answers ke saath

Short answerEasyNCERT in-text Q1, p. 76
Meera thode se washing powder, yaani detergent, ke saath hila kar check karna chahti hai ki uska tap water hard hai ya nahi. Kya uska test kaam karega? Use iske bajaye kya use karna chahiye?
Solution dikhao
AnswerNahi; use soap use karna chahiye.
Nahi. Detergent hard aur soft dono paani mein ek jaisa jhaag banata hai, kyunki uske calcium aur magnesium salts ghul jaate hain, isliye koi fark nahi dikhega. Use soap use karna chahiye: hard water mein woh thoda jhaag aur safed, dahi jaisa scum deta hai.
Short answerMediumNCERT in-text Q2, p. 76
Washing machine kapdon ko bhigone ke bajaye ghumaati aur mathti rehti hai. Unhe saaf karne ke liye yeh hilana-dulana kyun zaroori hai?
Solution dikhao
AnswerYeh soap ko gandagi tak laata hai aur micelles ko baha le jaata hai.
Soap molecules ko fibres mein fasi oily gandagi tak pahunchna hota hai, aur bane hue micelles ko kapde se bahar paani mein kheencha jaana hota hai. Sirf bhigone se yeh bahut dheere hota hai. Mathna, ragadna ya peetna gandagi tak lagaataar naya soap solution laata hai. Yeh chiknai ko chhoti boondon mein todta hai jinhe micelles gher sakein, aur micelles ko kapde se bahar baha deta hai.

Recap

Summary aur key points

Halaanki crust aur hawa mein carbon kam hai, har living thing aur zyaadatar roz ke materials iske compounds se bane hain.
Carbon chaar electrons lene ya khone ke bajaye electrons share karta hai; electrons ka ek shared pair ek covalent bond hai (Section 4.1).
Ek, do ya teen shared pairs se single, double ya triple bonds bante hain. Covalent compounds ke melting aur boiling points kam hote hain aur woh poor conductors hote hain (Section 4.1).
Diamond, graphite aur fullerenes carbon ke allotropes hain: same atoms alag arrangements mein (Carbon ke Allotropes).
Catenation aur tetravalency ki wajah se carbon millions compounds banata hai: chains, branches aur rings, saturated ya unsaturated (Section 4.2, Section 4.2.2).
Alkanes ( $C_{n} H_{2 n + 2}$ ), alkenes ( $C_{n} H_{2 n}$ ) aur alkynes ( $C_{n} H_{2 n - 2}$ ) hydrocarbons hain; same formula lekin alag structures wale compounds isomers hain (Section 4.2.2).
–Cl, –OH, –CHO, C=O aur –COOH jaise functional groups compound ki chemistry tay karte hain (Section 4.2.3).
Homologous series ke members ka functional group same hota hai aur woh $C H_{2}$ (14 u) se alag hote hain; unki physical properties dheere-dheere badalti hain (Section 4.2.4).
IUPAC naam carbons ki sankhya ke stem ko group ke prefix ya suffix se jodta hai (Section 4.2.5).
Carbon compounds jalkar heat aur light ke saath carbon dioxide aur paani dete hain; bahut kam hawa se soot wali flame milti hai (Section 4.3.1).
Alcohols oxidise hokar carboxylic acids bante hain, unsaturated compounds hydrogen jodte hain (jaise oils ke hydrogenation mein), aur alkanes sunlight mein chlorine ke saath substitution karte hain (Section 4.3.2, Section 4.3.3, Section 4.3.4).
Ethanol sodium ke saath react karta hai aur dehydrate hokar ethene banta hai; ethanoic acid ek weak acid hai jo esters banata hai aur bases, carbonates aur hydrogencarbonates ke saath react karta hai (Section 4.4.1, Section 4.4.2).
Soaps aur detergents oily gandagi ke aas-paas micelles banakar saaf karte hain; soap hard water mein scum banata hai, detergents nahi (Section 4.5).

Group activityNCERT Group Activity · p. 78

Models aur ghar ka bana soap

Tumhe chahiye

do rangon ki modelling clay aur toothpicks
soap ke liye: 25 mL nariyal ya moongphali ka tel, 35 mL 20 % sodium hydroxide solution, 8 g common salt, ek steel beaker aur ek stirrer

Models. Carbon ke liye clay ki badi balls banao aur hydrogen aur oxygen ke liye chhoti. Har carbon mein chaar toothpicks lagao, har oxygen mein do aur har hydrogen mein ek. Methane, ethane, ethene (carbons ke beech do toothpicks), ethanol aur butane ke do isomers banao. Kisi bhi carbon ki koi toothpick khaali nahi bachni chahiye.
Soap, apne teacher ke saath. Oil ko sodium hydroxide solution ke saath garam karo, lagaataar chalaate hue, 10 se 15 minute tak jab tak mixture gaadha na ho jaaye.
Salt daal kar chalao, jisse soap liquid se alag ho jaata hai. Use thanda hokar jamne do, phir shapes mein kaato. Jamne se pehle perfume ki kuch boondein milaayi ja sakti 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 mein	Yahan practice question
NCERT in-text Q1, p. 61	Practice 4.1 (NCERT ke in-text questions, p. 61) · Q1
NCERT in-text Q2, p. 61	Practice 4.1 (NCERT ke in-text questions, p. 61) · Q2
NCERT in-text Q1, p. 68	Practice 4.2 (NCERT ke in-text questions, pp. 68–69) · Q1
NCERT in-text Q2, p. 68	Practice 4.2 (NCERT ke in-text questions, pp. 68–69) · Q2
NCERT in-text Q3, p. 68	Practice 4.2 (NCERT ke in-text questions, pp. 68–69) · Q3
NCERT in-text Q4, p. 69	Practice 4.2 (NCERT ke in-text questions, pp. 68–69) · Q4
NCERT in-text Q5, p. 69	Practice 4.2 (NCERT ke in-text questions, pp. 68–69) · Q5
NCERT in-text Q1, p. 71	Practice 4.3 (NCERT ke in-text questions, p. 71) · Q1
NCERT in-text Q2, p. 71	Practice 4.3 (NCERT ke in-text questions, p. 71) · Q2
NCERT in-text Q1, p. 74	Practice 4.4 (NCERT ke in-text questions, p. 74) · Q1
NCERT in-text Q2, p. 74	Practice 4.4 (NCERT ke in-text questions, p. 74) · Q2
NCERT in-text Q1, p. 76	Practice 4.5 (NCERT ke in-text questions, p. 76) · Q1
NCERT in-text Q2, p. 76	Practice 4.5 (NCERT ke in-text questions, p. 76) · Q2
NCERT Exercises Q1	Exercises · Q1
NCERT Exercises Q2	Exercises · Q2
NCERT Exercises Q3	Exercises · Q3
NCERT Exercises Q4	Exercises · Q4
NCERT Exercises Q5	Exercises · Q5
NCERT Exercises Q6	Exercises · Q6
NCERT Exercises Q7	Exercises · Q7
NCERT Exercises Q8	Exercises · Q8
NCERT Exercises Q9	Exercises · Q9
NCERT Exercises Q10	Exercises · Q10
NCERT Exercises Q11	Exercises · Q11
NCERT Exercises Q12	Exercises · Q12
NCERT Exercises Q13	Exercises · Q13
NCERT Exercises Q14	Exercises · Q14
NCERT Exercises Q15	Exercises · Q15

Quick check: MCQs

Carbon ke Allotropes4 questions
4.2.2 Chains, Branches aur Rings4 questions
4.2.5 Carbon Compounds ki Nomenclature4 questions
4.3.4 Substitution Reaction4 questions
4.4.2 Ethanoic Acid ki Properties4 questions
4.5 Soaps aur Detergents4 questions

Glossary · 15

Key terms (English + Hindi)

addition reactionसंकलन अभिक्रियाsankalan abhikriya: Aisi reaction jismein atoms double ya triple bond par judte hain, jaise vegetable oils ke hydrogenation mein.Chapter mein pehli baar yahan aaya →
allotropeअपररूपaparroop: Kisi element ka ek roop jismein uske atoms alag tarah se arranged hote hain; diamond aur graphite carbon ke allotropes hain.Chapter mein pehli baar yahan aaya →

catenationशृंखलनshrinkhalan: Kisi element ke atoms ki ek doosre se chains, branches ya rings mein bond banane ki ability; carbon mein yeh sabse zyaada hoti hai.Chapter mein pehli baar yahan aaya →
covalent bondसहसंयोजी आबंधsahsanyoji aabandh: Woh bond jo do atoms ke electrons ka ek pair share karne se banta hai; do ya teen shared pairs se double ya triple bond banta hai.

esterificationएस्टरीकरणesterikaran: Acid catalyst ki madad se carboxylic acid aur alcohol ki reaction, jisse meethi smell wala ester aur paani milte hain.

functional groupप्रकार्यात्मक समूहprakaaryaatmak samooh: Koi atom ya atoms ka group, jaise –OH ya –COOH, jo carbon compound ki chemical properties tay karta hai.Chapter mein pehli baar yahan aaya →

homologous seriesसमजातीय श्रेणीsamjaatiya shreni: Same functional group wale compounds ki family jismein lagaataar aane wale members ek $C H_{2}$ unit (14 u) se alag hote hain.Chapter mein pehli baar yahan aaya →

micelleमिसेलmisel: Paani mein soap molecules ki ek ball jismein oily tails andar aur ionic heads bahar hote hain; yeh oily gandagi ko pakad sakti hai.Chapter mein pehli baar yahan aaya →

oxidising agentउपचायकupchaayak: Woh substance jo kisi doosre substance mein oxygen jodta hai, jaise alkaline potassium permanganate.Chapter mein pehli baar yahan aaya →

saponificationसाबुनीकरणsaabunikaran: Alkali se ester ka alcohol aur acid ke salt mein tootna; soap aise hi banta hai.Chapter mein pehli baar yahan aaya →
saturated compoundसंतृप्त यौगिकsantript yaugik: Aisa carbon compound jiske carbon atoms ke beech sirf single bonds hon, jaise ethane.Chapter mein pehli baar yahan aaya →
structural isomersसंरचनात्मक समावयवीsanrachnatmak samaavayavi: Same molecular formula lekin alag structures wale compounds, jaise butane aur 2-methylpropane.Chapter mein pehli baar yahan aaya →
substitution reactionप्रतिस्थापन अभिक्रियाpratisthaapan abhikriya: Aisi reaction jismein molecule ka ek atom ya group doosre ki jagah leta hai, jaise methane mein Cl ka H ki jagah lena.Chapter mein pehli baar yahan aaya →

tetravalencyचतुःसंयोजकताchatuh-sanyojakta: Valency chaar hona: har carbon atom chaar covalent bonds banata hai.Chapter mein pehli baar yahan aaya →

unsaturated compoundअसंतृप्त यौगिकasantript yaugik: Aisa carbon compound jismein carbon atoms ke beech kam se kam ek double ya triple bond ho, jaise ethene.Chapter mein pehli baar yahan aaya →

Carbon and its Compounds: Class 10 Science Chapter 4 Hinglish mein

Is chapter mein aap kya seekhenge

4.1 Carbon mein Bonding – Covalent Bond

Carbon ke Allotropes

Practice 4.1 (NCERT ke in-text questions, p. 61): answers ke saath

4.2 Carbon ka Versatile Nature

4.2.1 Saturated aur Unsaturated Carbon Compounds

4.2.2 Chains, Branches aur Rings

4.2.3 Kya Tum Mere Dost Banoge?

4.2.4 Homologous Series

4.2.5 Carbon Compounds ki Nomenclature

Practice 4.2 (NCERT ke in-text questions, pp. 68–69): answers ke saath

4.3 Carbon Compounds ki Chemical Properties

4.3.1 Combustion

4.3.2 Oxidation

4.3.3 Addition Reaction

4.3.4 Substitution Reaction

Practice 4.3 (NCERT ke in-text questions, p. 71): answers ke saath

4.4 Kuch Important Carbon Compounds – Ethanol aur Ethanoic Acid

4.4.1 Ethanol ki Properties

4.4.2 Ethanoic Acid ki Properties

Practice 4.4 (NCERT ke in-text questions, p. 74): answers ke saath

4.5 Soaps aur Detergents

Practice 4.5 (NCERT ke in-text questions, p. 76): answers ke saath

Summary aur key points

Practice questions answers ke saath (NCERT “Exercises”)

Apna NCERT exercise question dhoondo

Quick check: MCQs

Key terms (English + Hindi)

Tum chapter ke end tak pahunch gaye