A Level Chemistry (A2) chapter 11: Carboxylic acids and derivatives MCQs with answers
By Team Megalecture · Updated 4 Nov 2026
71 exam-style questions on Carboxylic acids and derivatives, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.
Ten Carboxylic acids and derivatives questions with answers
Try each one, then open the answer. These ten stay the same; the test draws new ones every time.
1. Which reagent gives a positive result with methanoic acid but not with ethanoic acid?
A
Tollens' reagent, warmed
B
NaHCO3(aq)
C
sodium metal
D
magnesium ribbon
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Answer: A. Methanoic acid, HCOOH, contains an H–C=O group and is oxidised to CO2 and water, reducing Ag+ to a silver mirror. Both acids react with carbonates, sodium and magnesium, so those do not distinguish them.
2. 3-chloropropanoyl chloride, ClCH2CH2COCl, is added to cold water containing aqueous silver nitrate at room temperature. How many moles of AgCl are precipitated immediately per mole of the compound?
A
0
B
0.5
C
1
D
2
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Answer: C. Only the acyl chloride group is hydrolysed at once in cold water, releasing one Cl− that gives AgCl. The C–Cl bond of the primary alkyl chloride is hydrolysed only slowly, so 2 mol is not formed immediately.
3. Which acid has the lowest pKa?
A
propanoic acid, CH3CH2COOH
B
3-chloropropanoic acid, ClCH2CH2COOH
C
2-chloropropanoic acid, CH3CHClCOOH
D
2,2-dichloropropanoic acid, CH3CCl2COOH
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Answer: D. Lowest pKa means strongest acid. Two Cl atoms on the carbon next to –COOH withdraw the most electron density, best stabilising the carboxylate ion. A Cl further away (C3) has a smaller effect, and propanoic acid has none.
4. 1.88 g of phenol reacts with excess ethanoyl chloride, giving phenyl ethanoate, CH3COOC6H5, in 85% yield. What mass of ester is obtained?
A
1.60 g
B
2.31 g
C
2.72 g
D
3.20 g
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Answer: B. n(phenol) = 1.88 ÷ 94.0 = 0.0200 mol; Mr(C8H8O2) = 136.0, so 0.0200 × 0.85 × 136.0 = 2.31 g. 2.72 g ignores the yield and 3.20 g divides by 0.85.
5. Ethanol gives an ester when heated with ethanoic acid and a little concentrated H2SO4, but phenol gives very little ester this way. Which reagent should be used to make phenyl ethanoate from phenol?
A
ethanoic acid with more concentrated H2SO4, heated for longer
B
ethanoic acid with anhydrous AlCl3, heated
C
ethanoyl chloride at room temperature
D
ethanal with acidified K2Cr2O7
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Answer: C. The acyl chloride is reactive enough to be attacked by the weakly nucleophilic phenol oxygen, giving CH3COOC6H5 and HCl. Longer heating with the acid does not overcome the problem.
6. Pentanoyl chloride reacts with methanol at room temperature. What is the organic product?
A
methyl pentanoate
B
pentyl methanoate
C
methyl butanoate
D
pentyl methyl ether
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Answer: A. CH3CH2CH2CH2COCl + CH3OH → CH3CH2CH2CH2COOCH3 + HCl. The ester is named alkyl (from the alcohol) then alkanoate (from the acyl chloride, counting the carbonyl carbon). Pentyl methanoate swaps the two parts.
7. Phenol reacts with ethanoyl chloride at room temperature. What is the name of the ester formed?
A
benzyl ethanoate
B
ethyl benzoate
C
phenyl ethanoate
D
methyl benzoate
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Answer: C. The phenyl group comes from phenol and the ethanoate from ethanoyl chloride: CH3COOC6H5. Benzyl ethanoate would need phenylmethanol, C6H5CH2OH.
8. After phenyl benzoate is made from phenol and benzoyl chloride, the crude solid is washed with NaHCO3(aq). What does this wash remove?
A
unreacted phenol, by forming CO2 with it
B
water, which NaHCO3 absorbs
C
the phenyl benzoate, which dissolves as a sodium salt
D
benzoic acid and HCl, by converting them into soluble sodium salts
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Answer: D. Any benzoyl chloride hydrolysed by moisture gives benzoic acid; it and HCl are acidic enough to react with HCO3−, forming soluble salts and CO2. Phenol is too weak an acid to react with NaHCO3, and the ester is neutral.
9. Which pair of reagents gives phenyl propanoate, CH3CH2COOC6H5, at room temperature?
A
phenol and propanoic acid with a few drops of concentrated H2SO4
B
propan-1-ol and benzoyl chloride
C
phenol and propanoyl chloride
D
benzoic acid and propan-1-ol
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Answer: C. Phenol is too weak a nucleophile to react usefully with a carboxylic acid, so an acyl chloride is needed: propanoyl chloride supplies CH3CH2CO–. Propan-1-ol with benzoyl chloride gives propyl benzoate, an isomer.
10. What is the molecular formula of phenyl benzoate?
A
C13H12O2
B
C14H12O2
C
C12H10O2
D
C13H10O2
Show answer
Answer: D. Phenyl benzoate is C6H5COOC6H5: 6 + 1 + 6 = 13 C, 5 + 5 = 10 H and two O. C14H12O2 is phenylmethyl benzoate, C6H5COOCH2C6H5.
Carboxylic acids and derivatives: questions students ask
How many Carboxylic acids and derivatives MCQs are there?
71, each with the answer and a short explanation, across 3 topics: Carboxylic acids, Esters, Acyl chlorides. Every chapter test draws ten of them, so you can take it many times.
Is the A Level Chemistry (A2) chapter 11 test free?
Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.
How is the chapter test marked?
The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.
