Question

Which from following functional groups has highest priority order for naming the poly functional compound?

• A. -CN
• B. $-\text{CONH}_2$
• C. $-\text{C} \equiv \text{C}-$
• D. $-\text{NH}_2$

Hint:

Acid derivatives (Amides) generally sit higher in priority than nitriles, which sit higher than simple nitrogen or carbon-carbon multiple bonds.

Answer 1

The Correct Option is B

Step 1: Concept
In IUPAC nomenclature of polyfunctional compounds, the principal functional group is determined by a fixed priority series.

Step 2: Meaning
The principal group is named as a suffix, while other groups are named as substituents (prefixes).

Step 3: Analysis
According to IUPAC rules, the priority order for the given groups is: Amide ($-\text{CONH}_2$) > Nitrile ($-\text{CN}$) > Amine ($-\text{NH}_2$) > Alkyne ($-\text{C} \equiv \text{C}-$).

Step 4: Conclusion
Therefore, the amide group ($-\text{CONH}_2$) has the highest priority among the choices. Final Answer: (B)