SSLC Science : Carbon and Its Compounds | Important Questions & Answers 2025

If you're getting ready for your SSLC 2025 Science exam, Carbon and Its Compounds is a chapter you absolutely can’t afford to overlook. It’s one of the most important topics, with high-weightage questions appearing in both the Chemistry theory and practical sections.

In this post, you’ll find all the key one-mark, three-mark, and five-mark questions from this chapter — clearly explained in simple, exam-focused language to help you revise smarter and score better. Let’s make acing this chapter easy and stress-free!

1. What is a Covalent Bond?

   A chemical bond formed by the sharing of electrons between two atoms.

   📘 Example: Hydrogen molecule (H–H) where each H atom shares one electron.

2. Types of Covalent Bonds with Examples

Type	Example	Bond Description
Single	H–H	Shares 1 pair of electrons
Double	O=O	Shares 2 pairs
Triple	N≡N	Shares 3 pairs

3. Electron-Dot Structures (Methane, Carbon Dioxide, Ethane)

4. Difference Between Saturated and Unsaturated Hydrocarbons

Saturated Hydrocarbon	Unsaturated Hydrocarbon
Single C–C bonds only	Has C=C or C≡C bonds
Burns with clean blue flame	Burns with sooty yellow flame
Shows substitution reaction	Shows addition reaction
Less reactive	More reactive
Example: Methane	Example: Ethene

5. What is Isomerism?

   Compounds with same molecular formula but different structures.

   Example: n-Pentane and iso-Pentane have the same formula (C₅H₁₂) but different arrangements.

6. Structures of Common Carbon Compounds

   1. Pentane (C₅H₁₂)

   2. Butane (C₄H₁₀)

   3. Hexane (C₆H₁₄)

   4. Benzene (C₆H₆) – cyclic ring

   5. Cyclohexane (C₆H₁₂) – closed ring of single bonds

7. What is a Homologous Series?

   A series of carbon compounds having the same functional group and similar chemical properties, differing by –CH₂– unit.

   Example: Methane (CH₄), Ethane (C₂H₆), Propane (C₃H₈)

8. What are Functional Groups?

   Groups of atoms that give specific properties to a compound, regardless of the carbon chain.

Group	Example
–OH (Alcohol)	Ethanol
–COOH (Carboxylic acid)	Ethanoic acid
–CHO (Aldehyde)	Propanal
–CO– (Ketone)	Propanone
–Cl / –Br (Halogen)	Bromoethane

9. How alcohol converted into carboxylic acid

   Alcohol is oxidised by potassium permanganate (KMnO₄) to form carboxylic acid.Alcohol is converted into carboxylic acid by the process of oxidation that is using a agent called Potassium permanganate

10. Addition Reaction – Definition & Use

    Unsaturated hydrocarbon + Hydrogen (catalyst) → Saturated hydrocarbon. Used in hydrogenation of vegetable oils to make ghee.

11. Substitution Reaction with Example

    In presence of sunlight, one atom in a compound is replaced by another.

    Example: CH₄ + Cl₂ → CH₃Cl + HCl

12. ............and .........are major Air Pollutants

    Sulphur dioxide (SO₂)

    Nitrogen dioxide (NO₂)

13. What is Combustion?

    Burning of carbon or carbon compounds in oxygen → CO₂ + Heat + Light. Combustion reaction is a chemical reaction in which carbon in all its allotropic forms burns in oxygen to give carbon dioxide, heat and light

14. Hydrogenation Reaction & Industrial Use

    Hydrogenation is a chemical reaction between hydrogen and other compound in the presence of a catalyst. Application: petrochemical industry, it is also used to prepare vegetable ghee from vegetable oil

15. Esterification Reaction

    Reaction in which carboxylic acid and alcohol combines to form Ester and water with the help of sulphuric acid Carboxylic acid + Alcohol → Ester + Water (using H₂SO₄). Esters are sweet-smelling compounds used in perfumes.

16. What is a saponification?

    Fats or oils + NaOH/KOH → Soap + Glycerol

17. Soaps & Cleaning Action

    Soap = Sodium/Potassium salt of long-chain acid.

    Forms micelles that trap oil/dirt — hydrophobic tails towards oil, hydrophilic heads towards water.

18.  Mention the versatile nature of Carbon

    • Tetravalency – forms 4 bonds

    • Catenation – links with other carbons to make chains and rings

19. Draw the structure of micelles

20. What happens when ethanol reacts with concentrated sulphuric acid write its reaction

    Dehydration reaction takes place