22 multiple-choice (MCQ / objective) questions from this chapter, in every exam-style shape used in the paper. Every question comes with an explanation along with the answer, so you remember why the option is correct, not just which one it is.
1 Direct Questions
Direct Questions
- 1 markWhat is the atomic number of carbon?
(A) 6(B) 4(C) 8(D) 12 - 1 markHow many valence electrons does a carbon atom have?
(A) 2(B) 4(C) 6(D) 8 - 1 markWhich of these molecules has a triple covalent bond?
(A) H₂(B) N₂(C) O₂(D) CH₄ - 1 markWhich carbon allotrope is described as the hardest substance known?
(A) Graphite(B) Fullerene(C) Charcoal(D) Diamond - 1 markWho prepared urea from ammonium cyanate, disproving the “vital force” theory?
(A) Friedrich Wöhler(B) John Dalton(C) Antoine Lavoisier(D) Dmitri Mendeleev - 1 markWhat general formula does the chapter give directly for alkenes?
(A) CₙH₂ₙ₊₂(B) CₙH₂ₙ(C) CₙH₂ₙ₋₂(D) CₙHₙ - 1 markA homologous series is a set of compounds in which:
(A) Every member carries a different functional group(B) All members share the same molecular formula(C) The same functional group substitutes for hydrogen in carbon chains of different lengths(D) Only carbon and hydrogen atoms are present - 1 markIn the reaction CH₄ + Cl₂ -> CH₃Cl + HCl, taking place in sunlight, what type of reaction is occurring?
(A) Addition reaction(B) Oxidation reaction(C) Substitution reaction(D) Saponification - 1 markWhat is the molecular formula of benzene, the ring compound the chapter names alongside cyclohexane?
(A) C₆H₁₂(B) C₆H₁₄(C) C₅H₁₀(D) C₆H₆
2 Assertion-Reason
Assertion-Reason
- 1 markAssertion (A): Graphite is a good conductor of electricity.
Reason (R): Graphite conducts electricity because it is a metal.
(A) A is true, R is true, R is the correct explanation(B) A is true, R is true, R is NOT the correct explanation(C) A is true, R is false(D) A is false, R is true - 1 markAssertion (A): Ethanoic acid is a strong acid, just like hydrochloric acid.
Reason (R): Carboxylic acids such as ethanoic acid ionise only partially in water, unlike mineral acids which ionise completely.
(A) A is true, R is true, R is the correct explanation(B) A is true, R is true, R is NOT the correct explanation(C) A is true, R is false(D) A is false, R is true
3 Match the Following
Match the Following
- 1 markMatch Column A with Column B:
A: 1. Alcohol 2. Aldehyde 3. Ketone 4. Carboxylic acid
B: (i) -CHO (ii) -COOH (iii) -OH (iv) -CO-
(A) 1-i, 2-ii, 3-iii, 4-iv(B) 1-iii, 2-i, 3-iv, 4-ii(C) 1-iv, 2-iii, 3-i, 4-ii(D) 1-ii, 2-iv, 3-i, 4-iii - 1 markMatch the reaction type (Column A) with its example (Column B):
A: 1. Addition reaction 2. Substitution reaction 3. Esterification 4. Saponification
B: (i) CH₄ + Cl₂ → CH₃Cl + HCl, in sunlight (ii) Ester + NaOH → alcohol + sodium salt (iii) Unsaturated hydrocarbon + H₂, with a Ni/Pd catalyst → saturated hydrocarbon (iv) Acid + alcohol, with an acid catalyst → ester + water
(A) 1-iii, 2-i, 3-iv, 4-ii(B) 1-i, 2-iii, 3-ii, 4-iv(C) 1-iv, 2-ii, 3-i, 4-iii(D) 1-ii, 2-iv, 3-iii, 4-i
4 Statement-Based Questions
Statement-Based Questions
- 1 markStatement I: Diamond and graphite are both pure forms of carbon.
Statement II: Because they have the same chemical properties, they also have identical physical properties.
(A) Both true, II is the correct explanation(B) Both true, II is NOT the correct explanation(C) I true, II false(D) I false, II true - 1 markStatement I: Ethanol turns blue litmus paper red.
Statement II: Ethanoic acid turns blue litmus paper red, but ethanol does not, because ethanol is neutral while ethanoic acid is a weak acid.
(A) Both true, II is the correct explanation(B) Both true, II is NOT the correct explanation(C) I true, II false(D) I false, II true
5 Arrange in the Correct Order
Arrange in the Correct Order
- 1 markArrange the steps of soap’s cleaning action in the correct order: (i) the ionic head stays in the water while the hydrocarbon tail buries into the oily dirt (ii) agitation pulls the whole micelle, dirt included, away from the fabric (iii) soap molecules position themselves around a droplet of oily dirt (iv) a micelle forms, trapping the oil at its centre
(A) i-iii-ii-iv(B) iii-i-iv-ii(C) iv-iii-i-ii(D) ii-i-iii-iv - 1 markArrange the steps of making, then breaking down, an ester in the correct order: (i) sodium hydroxide is added to the ester (ii) ethanoic acid reacts with ethanol using an acid catalyst (iii) a sweet-smelling ester forms (iv) the ester breaks down into an alcohol and the sodium salt of the acid
(A) ii-iii-i-iv(B) i-ii-iii-iv(C) iii-ii-iv-i(D) ii-i-iii-iv
6 Fill in the Blanks
Fill in the Blanks
- 1 markConcentrated sulphuric acid acts as a ______ agent when it converts ethanol to ethene at 443 K.
(A) oxidising(B) reducing(C) dehydrating(D) catalytic
7 Odd One Out
Odd One Out
- 1 markPick the odd one out, based on the type of bond between the carbon atoms:
(A) Ethane(B) Ethene(C) Propane(D) Butane
8 Passage-Based Questions
Passage-Based Questions
Passage
A student burned three carbon compounds one by one on a spatula: naphthalene, camphor and ethanol, then held a metal plate above each flame (Activity 4.3). For naphthalene and camphor, a yellow flame appeared with a lot of black smoke, and the metal plate collected a black sooty deposit. For ethanol, the flame burned with almost no smoke, and the plate stayed clean.
- 1 markAccording to the passage, why did naphthalene and camphor produce a sooty, yellow flame while ethanol did not?
(A) Naphthalene and camphor are saturated compounds, and saturated compounds burn with a sooty flame(B) Ethanol undergoes incomplete combustion, so no carbon is released from it(C) The metal plate was cooler above the ethanol flame, so no soot could collect on it(D) Naphthalene and camphor undergo more incomplete combustion, releasing unburnt carbon as soot; ethanol burns more cleanly
Passage
A student took distilled water in one test tube and hard water in another, added a few drops of soap solution to each, and shook both vigorously for the same time (Activity 4.11). The distilled water produced plenty of foam immediately, while the hard water produced very little foam and a white curdy substance appeared floating in it. The experiment was then repeated with a detergent solution instead of soap: both the distilled water and the hard water produced good foam, with no curdy substance in either (Activity 4.12).
- 1 markAccording to the passage, why did the hard water produce a curdy substance with soap but not with the detergent?
(A) Soap reacts with calcium and magnesium salts in hard water to form an insoluble precipitate, while a detergent’s charged ends do not form such a precipitate(B) Detergents react with calcium and magnesium salts faster than soap, so they are used up before a precipitate can form(C) Soap forms an insoluble precipitate with the sodium ions in hard water, which detergents lack(D) Detergents are weak acids, so they neutralise the salts that make water hard
9 True / False
True / False
- 1 mark(A) Graphite has a layered hexagonal structure.
(B) The layers in graphite are held together by strong covalent bonds.
(A) A true, B true(B) A false, B true(C) A true, B false(D) A false, B false
Answer Key and Explanations
Direct Questions
- (A) Carbon’s atomic number is 6, as stated while the chapter works out its electron distribution.
- (B) Carbon has four electrons in its outermost shell, which is why it needs to gain, lose or share four electrons to become stable.
- (B) Each nitrogen atom contributes three electrons to form three shared pairs, a triple bond, in N₂.
- (D) The chapter states diamond is the hardest substance known, due to its rigid three-dimensional network of four bonds per carbon atom.
- (A) Friedrich Wöhler disproved the vital force theory in 1828 by preparing urea from ammonium cyanate.
- (B) The chapter states the alkene general formula directly as CₙH₂ₙ, starting from ethene.
- (C) This is the chapter’s own definition of a homologous series.
- (C) Chlorine atoms take the place of hydrogen atoms one by one in sunlight, so this is a substitution reaction, exactly as the chapter defines it.
- (D) Benzene, a ring compound mentioned in the chapter alongside cyclohexane (C₆H₁₂), has the molecular formula C₆H₆.
Assertion-Reason
- (C) A is true (graphite does conduct), but R is false: the chapter is explicit that this is unusual precisely because graphite is a non-metal, not a metal.
- (D) A is false: ethanoic acid is a weak acid, not a strong one. R is true and is exactly why: it ionises only partially, unlike a mineral acid.
Match the Following
- (B) Alcohol: -OH (iii); Aldehyde: -CHO (i); Ketone: -CO- (iv); Carboxylic acid: -COOH (ii), matching Table 4.3.
- (A) Addition: hydrogenation with a catalyst (iii); Substitution: chlorine replacing hydrogen in sunlight (i); Esterification: acid + alcohol → ester (iv); Saponification: ester + NaOH → alcohol + salt (ii).
Statement-Based Questions
- (C) I is true. II is false: diamond and graphite share the same chemical properties but have very different physical properties, because their carbon atoms are bonded differently.
- (D) I is false: ethanol is neutral to litmus. II is true and explains exactly why: ethanoic acid is acidic, ethanol is not.
Arrange in the Correct Order
- (B) Soap molecules first surround the oily dirt (iii), their tails bury in while heads stay in water (i), a micelle forms (iv), and agitation finally pulls it away (ii): iii-i-iv-ii.
- (A) Esterification happens first (ii), giving the ester (iii), then NaOH is added (i), breaking it down by saponification (iv): ii-iii-i-iv.
Fill in the Blanks
- (C) Concentrated sulphuric acid removes water from ethanol, so it acts as a dehydrating agent in this reaction.
Odd One Out
- (B) Ethane, propane and butane all have only single bonds between their carbon atoms (saturated); ethene has a double bond, so it is the odd one out.
Passage-Based Questions
- (D) A yellow, sooty flame comes from incomplete combustion, which deposits unburnt carbon; ethanol burns more completely and leaves the plate clean. (Saturated hydrocarbons generally give a clean flame, so the first option has it the wrong way round.)
- (A) This is exactly the difference the chapter draws between soap and detergents in hard water.
True / False
- (C) A is true. B is false: the layers are held by weak forces (which is why they slide over each other); the strong covalent bonds are only within a layer.
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