Carbon and Its Compounds

JKBOSE/CBSE
Carbon and its Compounds Class 10 Notes | Bonding & Homologous Series
Notes - Carbon Compounds - Class 10

Carbon & Its Compounds

Overview: Covalent bonding, Versatile nature, Homologous series, Soaps & Detergents.

1. Covalent Bond

Formed by sharing of electrons. Carbon has valency 4 (Tetravalent). Forms strong bonds.

Allotropes: Diamond (Hardest), Graphite (Conductor), Fullerene (C-60).

2. Versatile Nature

Catenation: Self-linking property to form long chains/rings.

Tetravalency: Bonds with H, O, N, S, Cl.

3. Hydrocarbons

  • Saturated: Alkanes (Single bond). Formula: CnH2n+2.
  • Unsaturated: Alkenes (Double bond, CnH2n), Alkynes (Triple bond, CnH2n-2).

4. Functional Groups

  • Alcohol (-OH): Methanol, Ethanol.
  • Aldehyde (-CHO): Methanal, Ethanal.
  • Ketone (>C=O): Propanone.
  • Carboxylic Acid (-COOH): Ethanoic acid (Acetic acid).

5. Chemical Properties

  • Combustion: C + O2 → CO2 + Heat + Light.
  • Oxidation: Ethanol → Ethanoic Acid (using Alkaline KMnO4).
  • Addition: Hydrogenation of vegetable oils (Unsaturated to Saturated).
  • Substitution: CH4 + Cl2 → CH3Cl + HCl (in Sunlight).

6. Soaps and Detergents

Soap: Sodium salt of long chain fatty acids. Cleansing action by Micelle formation. Does not work in hard water.

Detergent: Ammonium/Sulphonate salts. Works in hard water.

NCERT In-Text Questions (Solved)

Page 61

Q1. Electron dot structure of CO2.
O :: C :: O
Carbon shares 2 electrons with each Oxygen atom. Double bonds.
Q2. Electron dot structure of Sulphur (S8).
8 Sulphur atoms arranged in a ring shape (Crown shape), joined by single covalent bonds sharing 1 electron pair each.

Page 68

Q1. How many structural isomers for Pentane?
Three isomers:
1. n-Pentane (Straight chain)
2. Isopentane (2-methylbutane)
3. Neopentane (2,2-dimethylpropane)
Q2. Properties of Carbon for huge compounds?
1. Catenation (Self-linking).
2. Tetravalency (Valency of 4).
Q3. Formula and structure of Cyclopentane?
Formula: C5H10. Five carbon atoms in a ring, each attached to 2 hydrogens.
Q4. Electron dot structures.
(i) Ethanoic acid: CH3COOH
(ii) H2S: H:S:H
(iii) Propanone: CH3COCH3
(iv) F2: F:F
Q5. Homologous series?
Series of compounds with same functional group and similar chemical properties, differing by -CH2- unit. Eg: Alkanes (CH4, C2H6).

Page 71

Q1. Why is conversion of ethanol to ethanoic acid an oxidation reaction?
Because Oxygen is added to Ethanol and Hydrogen is removed.
CH3CH2OH + [O] → CH3COOH + H2O. (Using KMnO4).
Q2. Welding mixture: Ethyne + Air vs Ethyne + Oxygen.
Burning Ethyne in air is incomplete (sooty flame, less heat). Burning in Oxygen gives clean flame and high temperature needed for welding.

Page 74

Q1. Test to distinguish Alcohol and Carboxylic Acid?
Sodium Carbonate/Bicarbonate Test:
Acid reacts with Na2CO3 to give effervescence (CO2 gas). Alcohol does not react.
Q2. What are Oxidising Agents?
Substances capable of adding oxygen to others. Eg: Alkaline KMnO4, Acidified K2Cr2O7.

Page 76

Q1. Can you check if water is hard by using detergent?
No. Detergents lather easily in both hard and soft water. So, they cannot distinguish. Soaps are used (Scum formation in hard water).
Q2. Why micelle formation takes place?
Soap molecules have hydrophobic tail (dissolves in dirt/oil) and hydrophilic head (dissolves in water). They arrange in a spherical structure called micelle to trap dirt at center. It doesn't form in ethanol as soap dissolves completely in it.
Exercise Solutions - Carbon - Class 10

NCERT Exercise Questions

Complete solutions for Chapter 4 exercises.

Q1. Ethane (C2H6) has how many covalent bonds?
(b) 7 covalent bonds. (6 C-H bonds and 1 C-C bond).
Q2. Butanone is a four-carbon compound with which functional group?
(c) Ketone.
Q3. While cooking, if bottom of vessel gets blackened, it means?
(b) The fuel is not burning completely. (Incomplete combustion produces soot).
Q4. Explain nature of covalent bond using CH3Cl.
C forms 3 single bonds with H and 1 single bond with Cl by sharing electrons. All atoms achieve noble gas config (C: Octet, H: Duplet, Cl: Octet). Bond formed by equal sharing.
Q5. Electron dot structures.
(a) Ethanoic Acid: CH3-C(=O)-OH.
(b) H2S: H-S-H.
(c) Propanone: CH3-C(=O)-CH3.
(d) F2: F-F.
Q6. Homologous series?
Family of compounds with same functional group, general formula, and similar chemical properties. Successive members differ by -CH2 group (14u mass). Ex: Methanol, Ethanol, Propanol.
Q7. Physical and Chemical properties of Ethanol vs Ethanoic Acid.
Physical: Ethanol is liquid with pleasant smell. Ethanoic acid has vinegar smell, freezes in winter (Glacial).
Chemical: Ethanol is neutral, no reaction with NaHCO3. Acid is acidic, reacts with NaHCO3 to give CO2.
Q8. Why does micelle formation occur?
Soap molecules have polar head and non-polar tail. In water, tails avoid water and clump together facing inwards (trapping dirt), heads face outwards. In ethanol, soap is soluble, so no micelle forms.
Q9. Carbon and its compounds are used as fuels. Why?
Because they burn in air to release large amount of heat and light energy (Exothermic). They have high calorific value.
Q10. Hard water scum formation?
Hard water contains Calcium and Magnesium salts. Soap reacts with them to form insoluble precipitate called Scum (Calcium/Magnesium Stearate). This wastes soap.
Q11. Change in litmus for soap?
Soap is basic (salt of weak acid + strong base). It turns Red litmus Blue.
Q12. Evaluation of Hydrogenation.
Addition of Hydrogen to unsaturated hydrocarbons (oils) in presence of catalyst (Ni/Pd) to form saturated hydrocarbons (fats/ghee). Industrial application: Vegetable Ghee from Vegetable Oil.
Q13. Which of these undergo addition reaction? C2H6, C3H8, C3H6, C2H2, CH4.
Only unsaturated compounds undergo addition.
C3H6 (Propene) and C2H2 (Ethyne).
Q14. Test to differentiate Butter and Cooking Oil.
Bromine Water Test:
- Cooking Oil (Unsaturated) decolorises Bromine water.
- Butter (Saturated) does not change color.
Q15. Cleaning action of soap.
Soap molecule has Hydrophobic tail (oil-loving) and Hydrophilic head (water-loving). Tails attach to dirt (oil), heads stay in water. By agitation, dirt is pulled out of cloth into water in form of micelles and washed away.
Formulas & Facts - Carbon & Compounds - Class 10

Key Reactions & Facts

Functional groups, homologous series, and important compounds.

Functional Groups & Formulae

Alkane Formula CnH2n+2
Alkene Formula CnH2n
Alkyne Formula CnH2n-2
Alcohol -OH
Aldehyde -CHO
Ketone -CO-
Carboxylic Acid -COOH
Ethanol C2H5OH
Ethanoic Acid CH3COOH

50 Important Facts

1. Carbon has valency 4 (Tetravalent).
2. Carbon forms covalent bonds.
3. Catenation is self-linking property of Carbon.
4. Graphite and Diamond are allotropes of Carbon.
5. Graphite is a good conductor of electricity.
6. Diamond is the hardest substance.
7. Buckminsterfullerene has 60 carbon atoms shaped like a football.
8. Hydrocarbons contain only C and H.
9. Saturated compounds have single bonds.
10. Unsaturated compounds have double or triple bonds.
11. Alkanes are saturated hydrocarbons.
12. Alkenes and Alkynes are unsaturated.
13. Methane is the main component of Natural Gas / Biogas.
14. Homologous series differ by -CH2 unit.
15. Molar mass difference in homologous series is 14u.
16. Boiling point increases with molecular mass.
17. Combustion of carbon compounds is exothermic.
18. Saturated hydrocarbons burn with clean blue flame.
19. Unsaturated hydrocarbons burn with sooty yellow flame.
20. Oxidation of Ethanol gives Ethanoic Acid.
21. Alkaline KMnO4 is an oxidizing agent.
22. Addition reaction occurs in unsaturated hydrocarbons.
23. Nickel is used as catalyst in hydrogenation.
24. Vegetable oils are unsaturated (Good).
25. Animal fats are saturated (Bad).
26. Substitution reaction occurs in saturated hydrocarbons.
27. Ethanol is active ingredient in alcoholic drinks.
28. Ethanol is soluble in water in all proportions.
29. Denatured alcohol is ethanol made unfit for drinking.
30. Methanol is poisonous (causes blindness).
31. Ethanoic acid is commonly called Acetic Acid.
32. 5-8% solution of acetic acid is Vinegar.
33. Pure ethanoic acid is called Glacial Acetic Acid.
34. Esterification produces Esters.
35. Esters are sweet-smelling substances.
36. Esters are used in perfumes.
37. Saponification is hydrolysis of ester to form soap.
38. Soap is sodium salt of fatty acid.
39. Detergent is sodium salt of sulfonic acid.
40. Soap molecule has hydrophilic head (Ionic).
41. Soap molecule has hydrophobic tail (Carbon chain).
42. Micelles are clusters of soap molecules.
43. Hydrophobic tail attaches to dirt/oil.
44. Hydrophilic head points outwards to water.
45. Hard water contains Calcium and Magnesium salts.
46. Soap forms scum (insoluble ppt) with hard water.
47. Detergents work well even in hard water.
48. Detergents are non-biodegradable (pollution).
49. Vegetable oil to Ghee is Hydrogenation.
50. Covalent bonds are directional.
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