What is the correct decreasing priority order for the following principal functional groups? — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

According to the IUPAC priority table, Carboxylic acids ($-COOH$) are highest, followed by Sulphonic acids ($-SO_3H$), then Acid Amides ($-CONH_2$), and lower down are Aldehydes ($-CHO$).