Question

Which of the following acts as the nucleophile in step 4 of the haloform reaction?

• A. $X^{-}$ (Halogen)
• B. $H_{2}O$
• C. $O{H}^{-}$
• D. None of the above

Answer 1

The correct option is C $O{H}^{-}$

Iodoform test is used to check the presence of carbonyl compounds with the structure $R-CO-C{H}_3$ or alcohols with the structure $R-CH\left(OH\right)-C{H}_3$ in a given unknown substance.

When Iodine and sodium hydroxide are added to a compound that contains either a methyl ketone or a secondary alcohol with a methyl group in the alpha position, a pale yellow precipitate of iodoform or triiodomethane is formed. It can be used to identify aldehydes or ketones. If an aldehyde gives a positive iodoform test, then it must be acetaldehyde since it is the only aldehyde with a $C{H}_{3}C=O$ group.

Steps Involved in Iodoform Reaction:

Step-1: Halogenation of methyl ketone:

Formation of iodoform​:

Hence, the correct answer is option (c).