Question

What are A and B in the following reaction sequence? 

• A.
• B.
• C.
• D.

Hint:

When performing dehydration reactions, reagents like \( {P}_2{O}_5 \) are commonly used to remove water and form anhydrides or other dehydrated intermediates.

Answer 1

The Correct Option is A

The reaction sequence involves the conversion of \( {CH}_3{COOH} \) (acetic acid) through various intermediates to form the final product. Here's the breakdown of the sequence:

1. Step A: The reaction involves the dehydration of acetic acid (\( {CH}_3{COOH} \)) using phosphorus pentoxide (\( {P}_2{O}_5 \)) and heat (\( \Delta \)). This leads to the formation of an intermediate, which in this case is acetic anhydride (\( {(CH}_3{CO})_2{O} \)).
2. Step B: In the second step, acetic anhydride is hydrolyzed with water or an aqueous acid to form the final product, benzoic acid (\( {C}_6{H}_5{COOH} \)), which is an analgesic drug.

Thus, A is \( {P}_2{O}_5 \) and B is benzoic acid.

Therefore, the correct answer is (1).