Each of the following is warmed with excess $I X_{2}$ / $NaOH$ and then acidified. Which one gives iodoform together with an organic acid of molar mass 128 g/mol? (C 12, H 1, O 16)

Answer: A

1-Cyclohexylethan-1-ol has

CH X_{3} CH (OH) X^{-}

, is oxidised to the methyl ketone and then cleaved to cyclohexanecarboxylic acid,

C X_{7} H X_{12} O X_{2}

M = 84 + 12 + 32 = 128

. The cyclopentyl ketone gives an acid of

M = 114

. The other two have no methyl ketone unit.