DP Chemistry (last assessment 2024)

Test builder »

Question 22N.2.hl.TZ0.6e

Select a Test
Date November 2022 Marks available [Maximum mark: 1] Reference code 22N.2.hl.TZ0.6e
Level hl Paper 2 Time zone TZ0
Command term Justify, State Question number e Adapted from N/A
e.
[Maximum mark: 1]
22N.2.hl.TZ0.6e

2-Bromobutane can react with cyanide, CN−, in a nucleophilic substitution reaction.

(e)

State, with a reason, how the rate of reaction of cyanide with 2-chlorobutane differs from its rate of reaction with 2-bromobutane under the same conditions.

[1]

Markscheme

slower AND C-Cl bond is stronger «than C-Br»

OR

slower AND Br/Br− is a better leaving group ✔

Examiners report

About half the candidates were aware that it is the strength of the carbon-halogen bond, rather than its polarity, which determines the relative rate of the nucleophilic substitution reactions of different halogenoalkanes.

Syllabus sections