CAIE A Level Chemistry 9701 · Halogen compounds
Butan-2-ol reacts with hydrogen chloride gas to form 2-chlorobutane. The reaction can proceed through either an or an mechanism.
Compare the and mechanisms of nucleophilic substitution in terms of the number of steps, the timing of the bond-breaking and bond-forming, and the structure of the transition state or intermediate. Your answer should refer to the inductive effect of alkyl groups and explain which mechanism is more likely for the reaction of butan-2-ol.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Compare means: Give similarities or differences between two things, and say which side each point belongs to. Write each point as a pair, for example: A is X, whereas B is Y. Two separate descriptions rarely earn the marks.
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