Question

Pentan-2-one and Pentan-3-one can be distinguished by:

• A. Fehling’s test
• B. Sodium bicarbonate test
• C. Tollens’ test
• D. Iodoform test

Hint:

Remember: A positive Iodoform test indicates the presence of a methyl ketone or a secondary alcohol with a \( CH_3CH(OH)- \) group.

Answer 1

The Correct Option is D

Step 1: The Iodoform test is used to detect the presence of a methyl ketone group (\( CH_3CO- \)) or a compound with the structure \( CH_3CH(OH)- \).
Step 2: Pentan-2-one (\( CH_3COCH_2CH_2CH_3 \)) has a methyl ketone group, so it gives a positive Iodoform test.
Step 3: Pentan-3-one (\( CH_3CH_2COCH_2CH_3 \)) does not have a \( CH_3CO- \) group; it has a ketone flanked by ethyl groups, so it does not give the Iodoform test.
Step 4: Therefore, Pentan-2-one and Pentan-3-one can be distinguished by the Iodoform test.