Question

Identify 'A' in the following reaction.
A + Acetic anhydride \( \xrightarrow{\text{H}^+} \) Aspirin + Acetic acid}

• A. Acrylic acid
• B. Oxalic acid
• C. Salicylic acid
• D. Phthalic acid

Hint:

Aspirin is the product of the esterification of the phenolic group of salicylic acid.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks to identify the reactant 'A' which reacts with acetic anhydride in the presence of an acid catalyst (H\(^+\)) to produce Aspirin and Acetic acid. This reaction is a classic example of acetylation.
Step 2: Key Formula or Approach:
The reaction given is the synthesis of Aspirin. We need to know the chemical structure of Aspirin and the reactants involved in its preparation.
Aspirin is chemically known as acetylsalicylic acid. Its synthesis involves the acetylation of salicylic acid.
Step 3: Detailed Explanation:
The reaction is the esterification of the phenolic hydroxyl group (-OH) of salicylic acid using acetic anhydride.
The structure of Salicylic acid is a benzene ring with a carboxylic acid group (-COOH) and a hydroxyl group (-OH) at ortho positions.
The structure of Acetic anhydride is (CH\(_3\)CO)\(_2\)O.
The reaction proceeds as follows:
Salicylic acid (A) reacts with acetic anhydride. The acetyl group (CH\(_3\)CO-) from acetic anhydride replaces the hydrogen atom of the hydroxyl group of salicylic acid.
\[ \text{Salicylic acid} + \text{Acetic anhydride} \xrightarrow{\text{H}^+} \text{Acetylsalicylic acid (Aspirin)} + \text{Acetic acid} \] Therefore, the reactant 'A' is Salicylic acid.
Step 4: Final Answer:
Based on the synthesis reaction of Aspirin, the compound 'A' is Salicylic acid.