Question

Which from following is a correct priority order for selection of principal functional group for nomenclature of polyfunctional compound according to IUPAC system ?

• A. \(-\text{CHO} > -\text{CONH}_2 > -\text{OH} > -\text{C}\equiv \text{C}-\)
• B. \(-\text{CONH}_2 > -\text{CHO} > -\text{OH} > -\text{C}\equiv \text{C}-\)
• C. \(-\text{C}\equiv \text{C}- > -\text{OH} > -\text{CONH}_2 > -\text{CHO}\)
• D. \(-\text{C}\equiv \text{C}- > -\text{CHO} > -\text{CONH}_2 > -\text{OH}\)

Hint:

Amide ranks above aldehyde, then alcohol, then alkyne.

Answer 1

The Correct Option is B

Step 1: Recall the ranking logic:
Higher oxidation level of carbon with more bonds to heteroatoms gets a higher priority. Acid derivatives are at the top, then carbonyl compounds, then alcohols, then hydrocarbons with multiple bonds.

Step 2: Place the four groups:
Amide is an acid derivative (top). Aldehyde is a carbonyl compound (next). Alcohol comes after carbonyl groups. Alkyne is a pure hydrocarbon unsaturation and sits at the bottom.

Step 3: Match:
That gives amide > aldehyde > alcohol > alkyne, which is option (B).

Final Answer:
Option (B) shows the correct priority order. \[ \boxed{-\text{CONH}_2 > -\text{CHO} > -\text{OH} > -\text{C}\equiv\text{C}-} \]