AS Level · Chemistry 9701 · Organic chemistry

Carboxylic acids & derivatives: AS Level Chemistry questions with answers

Free Carboxylic acids & derivatives questions for AS Level Chemistry (9701), part of Organic chemistry. Each question has the answer and the marking points an examiner would look for.

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Carboxylic acids & derivatives practice questions

Question 1Multiple choice · 1 markA* challenge

Which reagent and condition convert propanoic acid into propanoyl chloride?

  1. A PCl5 at room temperature
  2. B Cl2, UV light
  3. C HCl(aq), heat
  4. D NaCl, concentrated H2SO4
Show answer

Answer: A

Question 2Multiple choice · 1 mark

What is observed when ethanoic acid is added to sodium carbonate?

  1. A an orange precipitate
  2. B a silver mirror
  3. C effervescence
  4. D no change
Show answer

Answer: C

Question 3Multiple choice · 1 mark

Which statement describes esterification?

  1. A Gives an orange precipitate with aldehydes and ketones
  2. B A technique measuring mass-to-charge ratios of ions
  3. C Reaction of a carboxylic acid with an alcohol, acid catalyst, giving an ester and water
  4. D A carbon atom bonded to four different groups
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Answer: C

Question 4Structured · 7 marksA* challenge

1.50 g of a carboxylic acid, RCOOH, was dissolved in water and made up to 250 cm3. 25.0 cm3 portions needed 17.05 cm3 of 0.100 mol dm−3 sodium hydroxide.

(a)

Calculate the amount of acid in 250 cm3 of solution.

[2]
(b)

Calculate Mr of the acid and identify it.

[2]
(c)

Write an equation for the reaction of RCOOH with sodium carbonate.

[1]
(d)

Name the reagent that reduces the acid and the type of product formed.

[2]
Show answers and mark scheme
PartAnswer and marking pointsMarks
(a)0.0171 mol
n(NaOH) = 1.71 × 10−3 mol C1
× 10 = 0.0171 mol A1
2
(b)88.0; butanoic acid
Mr = 88.0 A1
butanoic acid, CH₃CH₂CH₂COOH A1
2
(c)2RCOOH + Na₂CO₃ → 2RCOONa + H₂O + CO₂
2RCOOH + Na₂CO₃ → 2RCOONa + H₂O + CO₂ B1
1
(d)LiAlH₄; primary alcohol
LiAlH₄ (in dry ether) B1
primary alcohol B1
2
Question 5Structured · 4 marks

Carboxylic acids react to form esters and other derivatives.

(a)

Describe the conditions to make an ester from ethanoic acid and ethanol.

[2]
(b)

Name the ester formed and draw its structural formula.

[2]
Show answers and mark scheme
PartAnswer and marking pointsMarks
(a)conc H₂SO₄ catalyst; heat under reflux
concentrated sulfuric acid catalyst B1
heat (under reflux) B1
2
(b)ethyl ethanoate; CH₃COOCH₂CH₃
ethyl ethanoate B1
CH₃COOCH₂CH₃ B1
2
Question 6Structured · 9 marksA* challenge

1.00 mol of ethanoic acid and 1.20 mol of propan-1-ol were heated with a few drops of concentrated sulfuric acid until equilibrium was reached. The equilibrium mixture contained 0.55 mol of ester.

(a)

Name the ester formed and state the role of the sulfuric acid.

[2]
(b)

Calculate Kc for the reaction.

[3]
(c)

Give the products when the ester is heated with aqueous sodium hydroxide.

[2]
(d)

Explain why ethanoic acid is a stronger acid than ethanol.

[2]
Show answers and mark scheme
PartAnswer and marking pointsMarks
(a)propyl ethanoate; catalyst
propyl ethanoate B1
catalyst B1
2
(b)1.03
moles at equilibrium: acid 0.45, alcohol 0.65, ester and water 0.55 C1
Kc = [ester][water]/([acid][alcohol]) (volumes cancel) C1
= 1.03 A1
3
(c)sodium ethanoate and propan-1-ol
sodium ethanoate B1
propan-1-ol B1
2
(d)carboxylate ion delocalised
negative charge in the ethanoate ion is delocalised over two O atoms M1
so the anion is stabilised and H⁺ is lost more readily M1
2

More Organic chemistry questions

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Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in