Question

Which is the decreasing priority order of the given functional group?

• A. amide>aldehyde>ketone>amine>alkyne
• B. aldehyde>amide>ketone>amine>alkyne
• C. aldehyde>amide>amine>alkyne>ketone
• D. alkyne>aldehyde>amide>amine>ketone

Hint:

In functional group priority ordering, the reactivity and electronic effects of the functional groups determine their ranking. Carbonyl-containing groups typically take higher priority.

Answer 1

The Correct Option is A

Step 1: IUPAC Nomenclature Rules. In IUPAC nomenclature, functional groups are ranked based on the oxidation state of the principal carbon atom. Carbonyl groups typically rank higher than non-carbonyl groups.

Step 2: Comparing Carbonyl Derivatives. Among the given groups, the amide (R-CONH₂) is a derivative of a carboxylic acid and has the highest priority. It is followed by the simple carbonyl groups: aldehydes (R-CHO) and then ketones (R-CO-R). Aldehydes rank higher than ketones because the carbonyl carbon is at the end of the chain.

Step 3: Comparing with Non-Carbonyl Groups. Nitrogen-containing amines (R-NH₂) rank lower than carbonyl groups but higher than unsaturated hydrocarbons like alkynes (R-C≡C-R).

Conclusion: The priority sequence is Amide>Aldehyde>Ketone>Amine>Alkyne, which corresponds to option (A).