Prepare for your exams with this Class 10 Science Chapter 4 Test Paper on Carbon and Its Compounds. This 50-mark practice paper includes MCQs, chemical equations, short-answer questions, numerical and application-based questions, and long-answer questions with complete solutions to help you revise important concepts and improve your exam preparation.
Table of Contents
CLASS 10 SCIENCE – Test
Chapter 4: Carbon and its compound
Maximum Marks: 50 Time: 2 Hours
General Instructions
- All questions are compulsory.
- Write balanced chemical equations wherever required.
- Draw neat structural formulae wherever necessary.
- Show all steps in numerical questions.
Section A – Multiple-Choice Questions
10 × 1 = 10 marks
Q1. The ability of carbon to form bonds with other carbon atoms is called:
(a) Combustion
(b) Catenation
(c) Oxidation
(d) Substitution
Q2. The valency of carbon is:
(a) 1
(b) 2
(c) 3
(d) 4
Q3. Which of the following is a saturated hydrocarbon?
(a) Ethene
(b) Ethyne
(c) Ethane
(d) Benzene
Q4. The general formula of alkanes is:
(a) \(C_nH_{2n}\)
(b) \(C_nH_{2n+2}\)
(c) \(C_nH_{2n-2}\)
(d) \(C_nH_n\)
Q5. Which functional group is present in ethanol?
(a) –CHO
(b) –COOH
(c) –OH
(d) –CO–
Q6. The chemical formula of ethanoic acid is:
(a) CH₃OH
(b) CH₃COOH
(c) C₂H₆
(d) CH₄
Q7. Which gas is generally produced when an active metal reacts with a carboxylic acid?
(a) Oxygen
(b) Nitrogen
(c) Hydrogen
(d) Carbon dioxide
Q8. Which of the following is commonly used as a catalyst in the hydrogenation of vegetable oils?
(a) Nickel
(b) Sodium chloride
(c) Calcium carbonate
(d) Copper sulphate
Q9. Soap molecules form structures called ______ in water.
(a) Crystals
(b) Micelles
(c) Atoms
(d) Alloys
Q10. Which of the following represents an unsaturated hydrocarbon?
(a) CH₄
(b) C₂H₆
(c) C₃H₈
(d) C₂H₄
Section B – Very Short Answer Questions
5 × 2 = 10 marks
Q11. Why does carbon form covalent bonds instead of gaining or losing four electrons? (2)
Q12. Define catenation and tetravalency. (2)
Q13. Write the molecular formulae of the following compounds: (2)
(a) Propane
(b) Butene
Q14. What is a homologous series? Write any two characteristics of a homologous series. (2)
Q15. Write the names and functional groups of the following: (2)
(a) Ethanol
(b) Ethanoic acid
Section C – Short Answer Questions
4 × 3 = 12 marks
Q16. Explain the difference between saturated and unsaturated hydrocarbons. Give one example of each and write their molecular formulae. (3)
Q17. Write balanced chemical equations for the following reactions: (3)
(a) Combustion of methane in oxygen.
(b) Reaction of ethanol with sodium.
(c) Reaction of ethanoic acid with sodium hydrogen carbonate.
Q18. What is a covalent bond? Explain the formation of a covalent bond in a methane molecule with the help of its electron-sharing arrangement. (3)
Q19. Explain the following: (3)
(a) Why do carbon compounds generally have low melting and boiling points?
(b) Why are most carbon compounds poor conductors of electricity?
(c) Why does carbon form a large number of compounds?
Section D – Application-Based Questions
2 × 4 = 8 marks
Q20. A hydrocarbon has the molecular formula C₃H₆. Answer the following questions: (4)
(a) Is it saturated or unsaturated, assuming it is an open-chain hydrocarbon? (1)
(b) Name the homologous series to which it belongs. (1)
(c) Write its structural formula. (1)
(d) Write the chemical equation for its hydrogenation in the presence of a suitable catalyst. (1)
Q21. A student takes ethanol in a test tube and adds a small piece of sodium to it. Bubbles of gas are observed. (4)
(a) Name the gas evolved. (1)
(b) Write the balanced chemical equation for the reaction. (2)
(c) State one test that can be used to identify the gas. (1)
Section E – Long Answer Questions
2 × 5 = 10 marks
Q22. Answer the following questions about ethanol and ethanoic acid: (5)
(a) Write the molecular formula of ethanol and ethanoic acid. (1)
(b) What happens when ethanoic acid reacts with sodium hydrogen carbonate? Write the balanced equation. (2)
(c) What is esterification? Write the reaction between ethanol and ethanoic acid to form an ester. (2)
Q23. Answer the following questions about soaps and detergents: (5)
(a) Explain how soap molecules clean oily dirt from clothes. (2)
(b) What are micelles? (1)
(c) Why are soaps less effective in hard water? (1)
(d) State one advantage of detergents over soaps. (1)
Class 10 Science – Chapter 4 Solutions
Carbon and Its Compounds | 50-Mark Test Paper
Science World By Tushar Sir
Here are the complete solutions to all 23 questions, including correct options, balanced chemical equations, structural formulae, and explanations.
Section A – Multiple-Choice Questions
10 × 1 = 10 marks
| Q. No. | Correct answer | Explanation |
|---|---|---|
| 1 | (b) Catenation | Catenation is the ability of carbon atoms to bond with one another. |
| 2 | (d) 4 | Carbon has four valence electrons and generally forms four covalent bonds. |
| 3 | (c) Ethane | Ethane (C₂H₆) contains only single bonds between carbon atoms. |
| 4 | (b) \(C_nH_{2n+2}\) | This is the general formula for open-chain alkanes. |
| 5 | (c) –OH | Ethanol contains the hydroxyl functional group. |
| 6 | (b) CH₃COOH | This is the molecular formula of ethanoic acid. |
| 7 | (c) Hydrogen | Active metals reacting with carboxylic acids generally release hydrogen gas. |
| 8 | (a) Nickel | Nickel catalyses the addition of hydrogen to unsaturated vegetable oils. |
| 9 | (b) Micelles | Soap molecules form micelles that help remove oily dirt. |
| 10 | (d) C₂H₄ | Ethene contains a carbon–carbon double bond. |
Section B – Very Short Answer Questions
5 × 2 = 10 marks
Q11. Why does carbon form covalent bonds instead of gaining or losing four electrons? (2 marks)
Carbon has four electrons in its outermost shell. It would need to lose four electrons or gain four electrons to achieve a stable outer shell.
- Losing four electrons requires a large amount of energy.
- Gaining four electrons is difficult because of repulsion between electrons and the energy involved.
Therefore, carbon generally shares electrons with other atoms to form covalent bonds.
Q12. Define catenation and tetravalency. (2 marks)
Catenation: The ability of an element to form bonds with atoms of the same element, creating chains, branches or rings. Carbon exhibits extensive catenation.
Tetravalency: The property of carbon by which it forms four covalent bonds because it has four valence electrons.
Q13. Write the molecular formulae of propane and butene. (2 marks)
(a) Propane
Propane is an alkane containing three carbon atoms.
Formula: C3H8
(b) Butene
Butene is an alkene containing four carbon atoms and one carbon–carbon double bond.
Formula: C4H8
Q14. What is a homologous series? Give two characteristics. (2 marks)
A homologous series is a family of organic compounds having the same functional group and general formula, with successive members differing by CH2 unit.
Characteristics:
- Successive members differ in molecular mass by 14 u.
- Members have similar chemical properties because they contain the same functional group.
Example: Methane (CH₄), ethane (C₂H₆) and propane (C₃H₈) belong to the alkane series.
Q15. Write the names and functional groups of ethanol and ethanoic acid. (2 marks)
| Compound | Formula | Functional group |
|---|---|---|
| Ethanol | C₂H₅OH | Hydroxyl, –OH |
| Ethanoic acid | CH₃COOH | Carboxyl, –COOH |
Section C – Short Answer Questions
4 × 3 = 12 marks
Q16. Explain saturated and unsaturated hydrocarbons with examples. (3 marks)
Saturated hydrocarbons: These contain only single covalent bonds between carbon atoms. They are called alkanes.
Example: Ethane, C₂H₆.
Structural formula:
CH3CH3
Unsaturated hydrocarbons: These contain at least one carbon–carbon double or triple bond.
Example: Ethene, C₂H₄.
Structural formula:
CH2=CH2
Difference: Saturated hydrocarbons have only carbon–carbon single bonds, whereas unsaturated hydrocarbons contain carbon–carbon double or triple bonds.
Q17. Write balanced chemical equations. (3 marks)
(a) Combustion of methane in oxygen
Methane burns in oxygen to produce carbon dioxide and water.
CH_4+2O2 CO2+2H2O
(b) Reaction of ethanol with sodium
Ethanol reacts with sodium to form sodium ethoxide and hydrogen gas.
2C2H5OH + 2Na produce 2C2H5ONa+H2
(c) Reaction of ethanoic acid with sodium hydrogen carbonate
This reaction produces sodium ethanoate, water and carbon dioxide.
CH3COOH + NaHCO3 produce CH3COONa+ H2O + CO2
Q18. What is a covalent bond? Explain its formation in methane. (3 marks)
A covalent bond is a chemical bond formed when atoms share one or more pairs of electrons.
In methane (CH₄):
- Carbon has four valence electrons.
- Each hydrogen atom has one electron.
- Carbon shares one electron with each of four hydrogen atoms.
- Four shared electron pairs form four single covalent bonds.
Structural formula of methane:
Methane (CH₄)
H
|
H — C — H
|
H
Thus, carbon completes its octet and each hydrogen completes its duplet.
Q19. Explain the following. (3 marks)
(a) Why do carbon compounds generally have low melting and boiling points?
Most carbon compounds are covalent molecular substances. The forces between their molecules are generally weak, so relatively little energy is needed to separate the molecules.
(b) Why are most carbon compounds poor conductors of electricity?
Most carbon compounds do not contain freely moving ions or electrons, so they cannot conduct electricity effectively.
(c) Why does carbon form a large number of compounds?
Carbon forms many compounds because of its tetravalency (ability to form four covalent bonds) and catenation (ability to bond with other carbon atoms to form chains, branches and rings).
Section D – Application-Based Questions
2 × 4 = 8 marks
Q20. A hydrocarbon has the molecular formula C₃H₆. (4 marks)
(a) Is it saturated or unsaturated? (1 mark)
Assuming it is an open-chain hydrocarbon, C₃H₆ is unsaturated because it contains a carbon–carbon double bond.
Answer: Unsaturated hydrocarbon.
(b) Name its homologous series. (1 mark)
It belongs to the alkene series, which has the general formula \(C_nH_{2n}\) for open-chain alkenes with one double bond.
(c) Write its structural formula. (1 mark)
The compound is propene.
CH3-CH=CH2
(d) Write its hydrogenation reaction. (1 mark)
Propene reacts with hydrogen in the presence of a nickel catalyst to form propane.
\[ \boxed{\mathrm{CH_3CH=CH_2+H_2 \xrightarrow{Ni}CH_3CH_2CH_3}} \]
Q21. Ethanol reacts with sodium and bubbles of gas are observed. (4 marks)
(a) Name the gas evolved. (1 mark)
The gas is hydrogen (H₂).
(b) Write the balanced chemical equation. (2 marks)
\[ \boxed{\mathrm{2C_2H_5OH+2Na\rightarrow 2C_2H_5ONa+H_2}} \]
The products are sodium ethoxide and hydrogen gas.
(c) State one test to identify the gas. (1 mark)
Bring a burning splint near the collected gas. Hydrogen burns with a characteristic ‘pop’ sound.
Safety note: This test should only be demonstrated by a teacher using a small, controlled quantity of gas.
Section E – Long Answer Questions
2 × 5 = 10 marks
Q22. Ethanol and ethanoic acid. (5 marks)
(a) Write their molecular formulae. (1 mark)
- Ethanol: C2H5OH
- Ethanoic acid: CH3COOH
(b) What happens when ethanoic acid reacts with sodium hydrogen carbonate? (2 marks)
Ethanoic acid reacts with sodium hydrogen carbonate to form sodium ethanoate, water and carbon dioxide. Brisk effervescence occurs due to the release of carbon dioxide gas.
Balanced equation:
CH3COOH + NaHCO3 Produce CH3COONa + H2O + CO2
(c) What is esterification? Write the reaction. (2 marks)
Esterification is the reaction between a carboxylic acid and an alcohol to produce an ester and water, usually in the presence of concentrated sulphuric acid.
Ethanoic acid reacts with ethanol to form ethyl ethanoate.
CH3COOH + C2H5OH produce CH3COOC2H5+H2O
Ethyl ethanoate is an ester with a characteristic pleasant, fruity smell.
Q23. Soaps and detergents. (5 marks)
(a) Explain how soap molecules clean oily dirt. (2 marks)
A soap molecule has two parts:
- Hydrophilic head: Attracted to water.
- Hydrophobic tail: Attracted to oil and grease.
When soap is mixed with water, its hydrophobic tails attach to oily dirt while its hydrophilic heads remain in the water. Agitation helps form micelles that trap the oily dirt, allowing it to be washed away with water.
(b) What are micelles? (1 mark)
Micelles are clusters of soap molecules formed in water, with their hydrophobic tails directed inward towards the oily dirt and their hydrophilic heads facing outward towards the water.
(c) Why are soaps less effective in hard water? (1 mark)
Hard water contains calcium and magnesium ions. These react with soap to form insoluble substances called scum, reducing lather formation and cleaning efficiency.
(d) State one advantage of detergents over soaps. (1 mark)
Detergents generally clean effectively in hard water because they do not form the same insoluble scum that ordinary soaps form with calcium and magnesium ions.
Quick Answer Key for Revision
| Question | Final answer |
|---|---|
| Q13 | C₃H₈, C₄H₈ |
| Q15 | Ethanol: –OH; Ethanoic acid: –COOH |
| Q17(a) | CH₄ + 2O₂ → CO₂ + 2H₂O |
| Q17(b) | 2C₂H₅OH + 2Na → 2C₂H₅ONa + H₂ |
| Q17(c) | CH₃COOH + NaHCO₃ → CH₃COONa + H₂O + CO₂ |
| Q20 | Propene; CH₃–CH=CH₂ |
| Q21 | Hydrogen gas |
| Q22(c) | Ethyl ethanoate + water |
| Q23 | Micelles remove oily dirt; detergents work in hard water |
Class 10 Science Complete Study Guide – PDF
CBSE Class 10 Science Master Guide PDF – Complete Study Material 2026–27
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