OCR A-Level Chemistry Synthesis and analytical techniques (02), June 2019: Question 14

1 mark · Medium difficulty · Multiple Choice

Identify which of potassium hydroxide, ethanoyl chloride, and nitric acid can react with phenol.

Practise this question

Question

Multiple choice question 14 asking which of potassium hydroxide (1), ethanoyl chloride (2), and nitric acid (3) can react with phenol, with four options A (1, 2 and 3), B (Only 1 and 2), C (Only 2 and 3), and D (Only 1), along with a box for the answer.
Question text

14 Which chemical(s) can react with phenol?

1 Potassium hydroxide

2 Ethanoyl chloride

3 Nitric acid

A 1, 2 and 3

B Only 1 and 2

C Only 2 and 3

D Only 1

Your answer

[1]

Mark scheme

Show the mark scheme Mark scheme for question 14 showing the correct answer is A.

14 A 1 AO1.1

How to answer it

Chemical Reactions of Phenol

What this question tests

This question assesses your factual recall and understanding of the chemical properties and functional group reactions of phenol (C₆H₅OH). Specifically, it tests your knowledge of phenol's weak acidity (reacting with strong bases like potassium hydroxide), its esterification reactions with acyl chlorides (like ethanoyl chloride), and its electrophilic substitution reactions with concentrated or dilute nitric acid.

Question 14 Multiple Choice

Analysis of Statements

✅ Correct Answer: Option A (1, 2 and 3)

All three reagents react with phenol through distinct chemical pathways: neutralization, esterification, and electrophilic substitution.

Mark Awarded: 1 mark (AO1.1 - Demonstration of knowledge)

💡 Key Knowledge: Statement 1 (Potassium hydroxide)

  • Phenol is a weak acid (stronger than water/alcohols, but weaker than carboxylic acids).
  • It reacts with strong bases like KOH in a neutralization reaction to form a soluble salt (potassium phenoxide) and water.

💡 Key Knowledge: Statement 2 (Ethanoyl chloride)

  • Phenol contains a hydroxyl group (-OH) attached directly to a delocalized benzene ring.
  • Like alcohols, phenol reacts with acyl chlorides (such as CH₃COCl ) via a nucleophilic addition-elimination mechanism to produce an ester (phenyl ethanoate) and hydrogen chloride gas ( HCl ).

💡 Key Knowledge: Statement 3 (Nitric acid)

  • The lone pair of electrons on the oxygen atom of phenol's -OH group overlaps with the delocalized pi-system of the benzene ring.
  • This strongly activates the ring towards electrophilic substitution, allowing it to readily react with HNO₃ (nitric acid) to form nitrophenols even under mild conditions.

🧠 Exam Technique

  • In multiple-choice questions featuring numbered lists, evaluate each statement independently.
  • Confirming just two correct statements immediately eliminates options C and D, narrowing your choices down quickly. Double-checking the third statement secures the correct answer (A).

❌ Common Errors

  • Students often confuse phenol with aliphatic alcohols and assume phenol is neutral. Because of this misconception, they might rule out reaction with KOH .
  • Others forget that the activated benzene ring in phenol makes it reactive towards nitrating agents, incorrectly eliminating nitric acid.

Topics

Module 6: Organic chemistry and analysis · 6.1 Aromatic compounds, carbonyls and acids

Question and mark scheme from the OCR A-Level Chemistry examination, Synthesis and analytical techniques (02), June 2019. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.