Answer:
See image attached
Explanation:
a)
The full reaction mechanism of step 1 was obtained from Bartleby and attached to this answer. The steps involved in the reaction are:
1) Loss of Br- and formation of a carbocation
2) Attack of CH3CN on the carbocation
4) Formation of a quaternary nitrogen intermediate
5) Attack of water on the quaternary nitrogen intermediate
6) Loss of the water molecule
5) Formation of the amide product
b)
i) sodium hydroxide
ii) HCl
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I think the answer is C. (Increasing the number of variables in the experiment)