Chapter-wise Worksheets for Class 10 Science: Chapter 04 Carbon and Its Compounds
Access comprehensive chapter-wise worksheets for Chapter 04 Carbon and Its Compounds using the CBSE Class 10 Science Carbon and its Compounds Worksheet Set 11. Designed to align with the 2026-27 academic syllabus for Class 10 Science, these printable practice sets help students reinforce key concepts and improve their overall exam readiness.
Practice Class 10 Science Worksheets: Chapter 04 Carbon and Its Compounds
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Questions
Q1. Three compounds A, B and C have the general formula CₙH₂ₙ₊₂ and boiling points −162 °C, −42 °C and −0.5 °C respectively. (a) What type of compounds are they? (b) Which has the maximum number of carbon atoms? (c) To which homologous series do A and B belong? [3 marks]
View Answer & Explanation
Answer: (a) They are alkanes (saturated hydrocarbons).
(b) C, because boiling point rises with molecular mass; C is butane.
(c) Both A (methane) and B (propane) belong to the alkane series.
Teacher's Note:
1. Boiling points in a homologous series increase with the number of carbon atoms.
2. The three compounds are methane, propane and butane.
Q2. Two compounds contain four carbon atoms each and have the same molecular formula but different structures. (a) What are such compounds called? (b) Name them. (c) Describe their structural formulae. [3 marks]
View Answer & Explanation
Answer: (a) Isomers (structural isomers).
(b) n-Butane and isobutane (2-methylpropane); the formula is C₄H₁₀.
(c) n-Butane has a straight chain CH₃–CH₂–CH₂–CH₃; isobutane has a three-carbon chain with a CH₃ branch on the middle carbon, CH₃–CH(CH₃)–CH₃.
Teacher's Note:
1. Isomers differ in arrangement of atoms, not in the number of atoms.
2. Branching is possible only from four carbons onwards.
Q3. Two alkanes A and B have 4 and 6 carbon atoms respectively. (a) Name them. (b) State their physical states at room temperature. (c) What happens when A burns in excess air? [3 marks]
View Answer & Explanation
Answer: (a) A is butane and B is hexane.
(b) Butane is a gas; hexane is a liquid.
(c) Butane burns with a blue flame to form CO₂ and water, releasing heat: 2C₄H₁₀ + 13O₂ → 8CO₂ + 10H₂O.
Teacher's Note:
1. Alkanes burn completely in excess oxygen.
2. Larger alkanes burn with a more luminous, sooty flame.
Q4. Hydrogen is passed through mustard oil in the presence of nickel. (a) Give one difference in physical properties between the oil and the product. (b) Name the process. [2 marks]
View Answer & Explanation
Answer: (a) Mustard oil is a liquid at room temperature while the product (a saturated fat) is a solid.
(b) Hydrogenation.
Teacher's Note:
1. Nickel acts as a catalyst.
2. Vegetable ghee is made by this process.
Q5. Sugarcane juice mixed with yeast is kept in an airtight container. After a few days it froths and gives a strong smell. (a) Name the process. (b) Describe the changes. (c) Name the main product. (d) How is the product separated? [4 marks]
View Answer & Explanation
Answer: (a) Fermentation.
(b) Enzyme invertase of yeast converts sucrose into glucose and fructose; enzyme zymase converts glucose into ethanol and CO₂, which causes frothing.
(c) Ethanol.
(d) By distillation, since ethanol and water have different boiling points.
Teacher's Note:
1. Yeast works without oxygen in this process.
2. C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂.
Q6. An organic compound A is present in wine and beer. On heating with alkaline potassium permanganate or acidified potassium dichromate it forms B. (a) Identify A. (b) Write the equation. (c) Name B. [3 marks]
View Answer & Explanation
Answer: (a) A is ethanol.
(b) CH₃CH₂OH → CH₃COOH (oxidation with the oxidising agent and heat).
(c) B is ethanoic acid (acetic acid).
Teacher's Note:
1. Oxidising agents add oxygen to the alcohol group.
2. The oxidising agent is written above the arrow in the equation.
Q7. An organic compound A of formula C₂H₆O is used to sterilise skin and on oxidation gives an acid B with the same number of carbon atoms. Name A and B and write the equation. [3 marks]
View Answer & Explanation
Answer: A is ethanol (C₂H₅OH) and B is ethanoic acid (CH₃COOH).
C₂H₅OH + 2[O] → CH₃COOH + H₂O
Teacher's Note:
1. Alcohols are oxidised to carboxylic acids.
2. Oxygen comes from the oxidising agent used.
Q8. Write two tests to show that ethanoic acid is acidic. [2 marks]
View Answer & Explanation
Answer: 1. Litmus test: ethanoic acid turns blue litmus red.
2. Sodium hydrogen carbonate test: brisk effervescence of CO₂ is seen, which turns lime water milky.
Teacher's Note:
1. Acids also react with active metals to release hydrogen.
2. Ethanoic acid is a weak acid.
Q9. A test tube contains a brown liquid. Methane bubbled through it leaves the colour unchanged, but ethene decolourises it. (a) Name the liquid. (b) Write the reaction of ethene with it. (c) What conclusion do you draw? [3 marks]
View Answer & Explanation
Answer: (a) Bromine water.
(b) CH₂=CH₂ + Br₂ → CH₂Br–CH₂Br
(c) Ethene is unsaturated and undergoes addition, while methane is saturated and does not.
Teacher's Note:
1. The test is used to distinguish saturated from unsaturated hydrocarbons.
2. The brown colour disappears due to addition of bromine across the double bond.
Q10. An organic substance X turns blue litmus red and gives strong effervescence with sodium hydrogen carbonate. (a) What is its nature and probable name? (b) What causes the effervescence? (c) Write the equation with sodium hydrogen carbonate. [3 marks]
View Answer & Explanation
Answer: (a) X is a carboxylic acid, probably ethanoic acid.
(b) Release of CO₂ gas.
(c) CH₃COOH + NaHCO₃ → CH₃COONa + H₂O + CO₂
Teacher's Note:
1. Carboxylic acids contain the –COOH group.
2. The salt formed is sodium ethanoate.
Q11. An organic acid X (formula C₂H₄O₂) is a liquid that freezes in cold countries. On warming with ethanol and a few drops of conc. H₂SO₄, a sweet-smelling compound Y forms. (a) Identify X and Y. (b) Write the reaction. [3 marks]
View Answer & Explanation
Answer: (a) X is ethanoic acid (glacial acetic acid); Y is ethyl ethanoate.
(b) CH₃COOH + C₂H₅OH → CH₃COOC₂H₅ + H₂O (conc. H₂SO₄ as catalyst).
Teacher's Note:
1. This is an esterification reaction.
2. Esters are used in perfumes and flavouring.
Q12. Give reasons: (a) The air holes of a gas burner are adjusted when vessels get blackened. (b) Synthetic detergents can cause water pollution. [2 marks]
View Answer & Explanation
Answer: (a) Blackening means incomplete combustion due to too little air; opening the air holes gives a blue, sootless flame by complete combustion.
(b) Many detergents are non-biodegradable, so they persist in lakes and rivers and harm aquatic life.
Teacher's Note:
1. Soot is unburnt carbon.
2. Soaps are biodegradable but detergents are often not.
Q13. A non-metal X has two common allotropes A and B. A is very hard and a bad conductor of electricity; B is soft and a good conductor. Identify X and its allotropes and explain the difference. [3 marks]
View Answer & Explanation
Answer: X is carbon; A is diamond and B is graphite.
In diamond each carbon is bonded to four others in a rigid three-dimensional network with no free electrons. In graphite each carbon is bonded to three others in hexagonal layers that slide over each other, and the fourth electron is free to conduct.
Teacher's Note:
1. Properties depend on structure.
2. Graphite is used as a lubricant and in electrodes.
Q14. An organic compound A on heating with conc. H₂SO₄ forms B, which adds one mole of hydrogen in the presence of nickel to form C. One mole of C burns to give 2 moles of CO₂ and 3 moles of H₂O. Identify A, B and C and write the equations. [4 marks]
View Answer & Explanation
Answer: C is ethane (C₂H₆), B is ethene (C₂H₄) and A is ethanol (C₂H₅OH).
C₂H₅OH → C₂H₄ + H₂O (conc. H₂SO₄, heat)
C₂H₄ + H₂ → C₂H₆ (Ni)
2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O
Teacher's Note:
1. Start from the combustion data to find C and work backwards.
2. Conc. H₂SO₄ acts as a dehydrating agent.
Q15. You have three unlabelled test tubes containing ethanol, ethanoic acid and soap solution. How will you identify them using litmus paper and sodium metal? [3 marks]
View Answer & Explanation
Answer: Ethanoic acid turns blue litmus red. Soap solution (basic) turns red litmus blue. Ethanol changes neither litmus.
Sodium releases hydrogen gas with ethanol and with ethanoic acid, but not with soap solution; so after the litmus test the remaining tube is ethanol.
Teacher's Note:
1. Use one test per tube and note the observation.
2. Ethanol is neutral to litmus.
Q16. Why is scum formed only with hard water? State two disadvantages of scum. [3 marks]
View Answer & Explanation
Answer: Hard water contains calcium and magnesium salts; these react with soap to form insoluble calcium and magnesium salts of fatty acids called scum.
Disadvantages: soap is wasted and lather is poor; scum sticks to clothes and deposits on boiler walls or pipes.
Teacher's Note:
1. Detergents do not form scum because their calcium salts are soluble.
2. Soft water gives lather easily.
Q17. Why is a mixture of water and alcohol used in vehicle radiators in cold countries? Give two reasons. [2 marks]
View Answer & Explanation
Answer: Water would freeze below 0 °C and block the radiator. A water-alcohol mixture is homogeneous because the two are miscible in all proportions, and it has a much lower freezing point than water, so it does not freeze.
Teacher's Note:
1. Substances added to lower the freezing point are called antifreeze.
2. Ethylene glycol is also used.
Q18. A series of carbon compounds has the general formula CₙH₂ₙ₋₂ (first member has n = 2). Write the molecular formulae of the third and fifth members. [2 marks]
View Answer & Explanation
Answer: This is the alkyne series. Third member n = 4: C₄H₆; fifth member n = 6: C₆H₁₀.
Teacher's Note:
1. The first member is C₂H₂ (ethyne).
2. Each successive member differs by CH₂.
Free study material for Science
CBSE Class 10 Science Worksheets for Chapter 04 Carbon and Its Compounds
Daily Practice Questions for Class 10 Science
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