What is the product of the following reaction?
A)Only I
B)Only II
C)Only III
D)Only I and II

Question

What is the product of the following reaction? 
A)Only I 
B)Only II 
C)Only III 
D)Only I and II

Quizplus · Accepted Answer

The product of the given reaction will involve the heating of 2-bromobutane with excess potassium hydroxide (KOH) in ethanol. This type of reaction is called an elimination reaction as it eliminates a leaving group (here, the bromine atom) and a hydrogen atom from adjacent carbon atoms to form a C=C double bond.

I. The first step in the reaction is the formation of tert-butanol and potassium bromide by the nucleophilic substitution of OH- on the bromine atom of 2-bromobutane. This reaction is written as:

2-bromobutane + KOH → tert-butanol + KBr

This is an example of an SN2 reaction where hydroxide ion attacks the bromine atom, and the leaving group leaves simultaneously. Therefore, I is correct.

II. The next step involves the elimination of a proton from the tert-butanol formed above. This forms water and a carbocation intermediate, which quickly undergoes a deprotonation reaction with the OH- ion present in the reaction mixture, to form an alkene. A possible mechanism for this reaction is:

tert-butanol → H2O + tert-butyl carbocation
tert-butyl carbocation + OH- → 2-methylpropene

Therefore, II is correct.

III. Ethanol does not play a direct role in the reaction and therefore is not a product. Therefore, III is incorrect.

Since both I and II are correct, the answer is D - Only I and II.

What Is the Product of the Following Reaction