Answer the question on the basis of passage given below:
Alcohols and phenols are formed when a hydrogen atom in a hydrocarbon, aliphatic and aromatic respectively, is replaced by –OH group. The substitution of a hydrogen atom in a hydrocarbon by an alkoxy or aryloxy group forms ethers.
Alcohols and phenols consist of two parts, an alkyl/aryl group and a hydroxyl group. The properties of alcohols and phenols are primarily due to the hydroxyl group. The nature of alkyl and aryl groups simply modifies these properties. Alcohols react both as nucleophiles and electrophiles whereas in phenols, the reactions that take place on the aromatic ring are electrophilic substitution reactions.
Aspirin is an acetylation product of:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → o-Hydroxybenzoic acid
Aspirin is acetylsalicylic acid. It is made by acetylating the phenolic –OH group of salicylic acid (o-hydroxybenzoic acid) with acetic anhydride in the presence of a little acid:
\( \text{o-}\ce{HOC6H4COOH + (CH3CO)2O} \xrightarrow{\ce{H+}} \text{o-}\ce{CH3COOC6H4COOH + CH3COOH} \)
Aspirin is an analgesic and antipyretic, and also prevents platelet coagulation.
Why the other options are incorrect
Option (1) o-Dihydroxybenzoic acid — Incorrect. A benzoic acid with two OH groups; its acetylation would give a diacetyl compound, not aspirin, which has a single acetoxy group ortho to COOH.
Option (3) m-Hydroxybenzoic acid — Incorrect. Its acetyl derivative has the acetoxy group meta to COOH; aspirin is the ortho isomer.
Option (4) p-Dihydroxybenzene — Incorrect. This is hydroquinone (quinol), with no COOH group; acetylation gives hydroquinone diacetate.
NCERT (2026-27 edition):
Esterification – “Alcohols and phenols react with carboxylic acids, acid chlorides and acid anhydrides to form esters. … The introduction of acetyl (CH3CO) group in alcohols or phenols is known as acetylation. Acetylation of salicylic acid produces aspirin.”