AQA A-Level Chemistry Paper 3, 2021: Question 26

1 mark · Easy difficulty · Multiple Choice

This question checks your ability to identify the product of an oxidation reaction using a common oxidising agent—acidified potassium dichromate(VI). You must know what type of organic product forms from different classes of alcohols (primary, secondary, tertiary) and be able to deduce the correct structure from a list of organic compounds.

Practise this question

Question

AQA A-Level Chemistry Paper 3, 2021: Question 26
Question text

26 Which compound is produced when 1-phenylethanol reacts with

acidified potassium dichromate(VI)?

[1 mark]

A C6H5CH2CH2OH

B C6H5CH2CHO

C C6H5COCH3

D C6H5CH(OH)CH3

Mark scheme

Show the mark scheme Mark scheme for AQA A-Level Chemistry Paper 3, 2021: Question 26

26 C 1 C6H5COCH3

How to answer it

Multiple Choice Explained: Oxidation of 1-Phenylethanol

Correct Answer: C – C₆H₅COCH₃

Why? 1-Phenylethanol is a secondary alcohol. When oxidised with acidified potassium dichromate(VI), it forms a ketone. The correct ketone from 1-phenylethanol is phenylethanone (C₆H₅COCH₃).

Why A is incorrect:

C₆H₅CH₂CH₂OH is a primary alcohol and does not match the structure of 1-phenylethanol. This structure wouldn't be formed from the oxidation of 1-phenylethanol.

Why B is incorrect:

C₆H₅CH₂CHO is an aldehyde, but 1-phenylethanol is a secondary alcohol, which cannot be oxidised to an aldehyde — only primary alcohols oxidise to aldehydes.

Why D is incorrect:

C₆H₅CH(OH)CH₃ is the starting material (1-phenylethanol), not the product. The question asks for the product of oxidation.

Topics

Organic Chemistry · 3.3.5 Alcohols

Question and mark scheme from the AQA A-Level Chemistry examination, Paper 3, 2021. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.