OCR A-Level Chemistry Synthesis and analytical techniques (02), June 2018: Question 4

1 mark · Easy difficulty · Multiple Choice

Identify which chemical structure represents an alicyclic compound from the given multiple-choice options.

Practise this question

Question

Multiple choice question 4 asking which structure represents an alicyclic compound, with four options labeled A, B, C, and D. Option A shows naphthalene, option B shows styrene (vinylbenzene), option C shows a six-membered ring with two double bonds and a methyl group (1-methylcyclohexa-1,3-diene), and option D shows methylbenzene (toluene). An answer box and mark allocation of [1] are shown at the bottom.
Question text

4 Which structure represents an alicyclic compound?

A

B

C

D

Your answer

[1]

Mark scheme

Show the mark scheme The mark scheme table indicates the correct answer for question 4 is C, worth 1 mark.

4 C 1

How to answer it

Question 4: Identifying an Alicyclic Compound

What this question tests

This question assesses your ability to define and recognise core organic chemistry terminology, specifically distinguishing between aliphatic, alicyclic, aromatic, and cyclic structures from skeletal and displayed formulae.

Question Part 4

Multiple Choice Analysis

✅ Correct Answer: C

Structure C is a non-aromatic ring containing a carbon-carbon double bond (methylcyclohexa-1,3-diene derivative). Because it is a ring structure that does not possess aromatic (benzene-like) delocalised rings, it is classified as alicyclic.

💡 Key Knowledge

  • Alicyclic: An aliphatic compound arranged in a non-aromatic ring (with or without side chains).
  • Aromatic (Arene): Contains one or more benzene rings with delocalised pi electrons (seen in A, B, and D).
  • Aliphatic: Carbon and hydrogen joined in straight chains, branched chains, or non-aromatic rings.

🧠 Exam Technique

Scan all options for the presence of a benzene ring (a 6-membered carbon ring with an inner circle or alternating double bonds). Options A, B, and D all contain benzene rings, making them aromatic. By elimination, C is the only remaining option.

❌ Common Errors

Students frequently confuse cyclic aliphatic compounds with aromatic rings simply because they are closed loops. Remember that delocalised systems (benzene rings) are aromatic, not alicyclic.

Mark allocation: 1 mark available for selecting C.

Topics

Module 4: Core organic chemistry · 4.1 Basic concepts and hydrocarbons

Question and mark scheme from the OCR A-Level Chemistry examination, Synthesis and analytical techniques (02), June 2018. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.