Question

The correct decreasing order of priority for the functional group of organic compounds in the IUPAC method of nomenclature is

• A. –CHO > –OH > –CONH$_2$ > –COCl
• B. –CONH$_2$ > –CHO > –COCl > –OH
• C. –COCl > –CONH$_2$ > –CHO > –OH
• D. –CHO > –CONH$_2$ > –COCl > –OH

Hint:

When determining the priority of functional groups in IUPAC nomenclature, remember that acid derivatives like –COCl have higher priority than amides, which in turn rank above aldehydes and alcohols.

Answer 1

The Correct Option is C

Step 1: Understand functional group priority according to IUPAC. The IUPAC system ranks functional groups based on their ability to determine the suffix in nomenclature. The typical order of priority (from highest to lowest among the given options) is: \[ –COCl \, (\text{Acid chloride}) > –CONH_2 \, (\text{Amide}) > –CHO \, (\text{Aldehyde}) > –OH \, (\text{Alcohol}) \] Step 2: Analyze each option against this order. Only option (3) lists the functional groups in the correct decreasing order of priority as per IUPAC rules.