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

The question pertains to identifying the functional group with the highest priority for naming in a polyfunctional compound among the given options. Understanding the priority of functional groups is essential in IUPAC nomenclature. When multiple functional groups are present, their order of precedence determines the principal functional group, which influences the base name of the compound.

The functional groups given in the options are:

1. -CN (Cyano group)
2. $-\text{CONH}_2$ (Amide group)
3. $-\text{C} \equiv \text{C}-$ (Alkyne group)
4. $-\text{NH}_2$ (Amino group)

According to IUPAC nomenclature rules, the general order of precedence for these groups is as follows:

• Amide (-CONH₂): Highest priority among the provided options. It takes precedence over nitriles, alkynes, and amines.
• Nitrile (-CN): Generally follows amides in priority.
• Alkyne (-C≡C-): Lower priority than functional groups like amides and nitriles.
• Amino (-NH₂): Generally has the lowest priority among the groups listed.

Thus, the functional group with the highest priority for naming among the given options is the amide group (-CONH₂). This is because amides are ranked higher than nitriles, alkynes, and amines in the IUPAC nomenclature system.

In conclusion, when naming compounds with these functional groups, the presence of the amide group will determine the principal functional group for the naming process.