Question

Which of the following compounds will undergo racemisation when solution of KOH hydrolysis?

• A. (ii) and (iv)
• B. (iiI) and (iv)
• C. (i) and (iv)
• D. Only (iv)

Answer 1

The Correct Option is D

The question involves determining which compound undergoes racemization upon hydrolysis with a solution of KOH. Let's analyze each compound to understand the mechanism involved:

1. For compound (i), which is a benzyl chloride, hydrolysis will lead to the formation of benzyl alcohol. This does not involve the formation of a chiral center, hence does not lead to racemization.
2. Compound (ii) is a simple alkyl chloride (1-chloropropane). Its hydrolysis yields a primary alcohol, which also does not involve any chiral center, thus no racemization occurs.
3. Compound (iii) is (2-chlorobutane), which has a chiral center. However, racemization occurs when the reaction mechanism involves an SN1 reaction leading to the formation of a carbocation. With the presence of –CH₃ and –CH₂Cl substituents, SN1 is not favored, thus racemization is unlikely.
4. Compound (iv) is 2-chloropropane, which has a chiral carbon. In presence of KOH, an SN1 reaction mechanism takes place. This involves the formation of a planar carbocation intermediate which allows for racemization as the nucleophile can attack from either side, forming a racemic mixture.

Based on the above analysis, only compound (iv) will undergo racemization when hydrolyzed with KOH solution due to its ability to form a planar carbocation intermediate during an SN1 reaction.

Conclusion: The correct answer is Only (iv).