Question

What is IUPAC name of the ketone A, which undergoes iodo form reaction to give

CH₃ CH= C(CH₃)COONa and yellow precipitate of CHI₃ ?
(a) 3-Methylpent-3-en-2one
(b) 3-Methylbut-2-en- one
(c) 2, 3-Dimethylethanone
(d) 3-Methylpent-4-one

Answer 1

The correct IUPAC name for the ketone, which undergoes an iodoform reaction to give CH3CH=C(CH3)COONa and CHI3, is 3-Methylbutan-2-one.

Step-by-step explanation:

To identify the IUPAC name of the ketone, which undergoes a iodoform reaction to give CH3CH=C(CH3)COONa and yellow precipitate of CHI3, we need to determine the correct structure of the ketone before the reaction occurs. Based on the provided reaction products, the starting ketone must have a methyl group (CH3) attached to the carbon that carries the carbonyl group (C=O). The correct IUPAC name for the ketone is based on the longest carbon chain containing the carbonyl group and the position of the methyl group and the carbonyl within this chain.

Using the rules for nomenclature of ketones, the ketone group takes precedence in numbering the carbon chain. Thus, the correct IUPAC name is 3-Methylbutan-2-one (option b), where '3-Methyl' indicates the position of the methyl substituent on the third carbon, 'butan' refers to a four-carbon parent chain, and the '2-one' denotes the ketone group on the second carbon.