DP Chemistry (last assessment 2024)

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Question 20N.2.sl.TZ0.d(ii)

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Date November 2020 Marks available [Maximum mark: 1] Reference code 20N.2.sl.TZ0.d(ii)
Level sl Paper 2 Time zone TZ0
Command term Justify, Predict Question number d(ii) Adapted from N/A
d(ii).
[Maximum mark: 1]
20N.2.sl.TZ0.d(ii)

Chlorine undergoes many reactions.

Predict, giving a reason, whether ethane or chloroethane is more reactive.

[1]

Markscheme

chloroethane AND C–Cl bond is weaker/324 kJ mol−1 than C–H bond/414 kJ mol−1
OR
chloroethane AND contains a polar bond ✔


Accept “chloroethane AND polar”.

Examiners report

This was a challenging question that was answered correctly by only 30% of the candidates. A variety of incorrect answers were seen such as 'chlorine is a halogen and hence it is reactive', and 'ethane is more reactive because it is an alkane'. For students who answered correctly, the polarity was the most frequently given reason.

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