JEE Chemistry 2024 Question with Solution

Given: The question asks which test gives a positive result for a phenolic group.

Find: The correct test used to identify phenols.

A phenolic group contains a hydroxyl group attached to an aromatic ring.

From the provided solution text:

• Lucas test is used to distinguish primary, secondary, and tertiary alcohols.
• Carbylamine test is specific for primary amines.
• Tollen’s test is used to detect aldehydes.
• Phthalein dye test is specific for phenols and gives colored phthalein dye formation.

Therefore, the phenolic group is identified by a positive Phthalein dye test.

The correct option is A. The solution labels the option as C, but its written conclusion clearly states Phthalein test, which matches option A in the given options.

Given: Four named qualitative tests are listed.

Find: Which one is specific for phenolic groups.

Eliminate the tests by their known use:

• Lucas test $\rightarrow$ alcohol classification
• Tollen’s test $\rightarrow$ aldehydes
• Carbylamine test $\rightarrow$ primary amines

The remaining relevant test is Phthalein dye test, which is used for phenols.

Therefore, the correct option is A.