Reaction of Butan-2-one with Ethyl magnesium bromide followed by hydrolysis

The given reaction can be represented as:

Butan-2-one + Ethyl magnesium bromide → (after hydrolysis) → Tertiary alcohol

Explanation:

- Butan-2-one is a ketone having a carbonyl group in its structure. The carbonyl group contains a carbon-oxygen double bond. Ketones can be reacted with organometallic reagents like Grignard reagents to form alcohols.
- Ethyl magnesium bromide (C2H5MgBr) is an organometallic compound of magnesium and is commonly used as a Grignard reagent in organic synthesis. It is a strong nucleophile and reacts with the carbonyl group of Butan-2-one to form a new carbon-carbon bond.
- The reaction of Butan-2-one with Ethyl magnesium bromide produces a new molecule having a magnesium-carbon bond. This molecule is highly reactive and unstable and must be hydrolyzed to obtain the final product.
- Hydrolysis is the process of breaking a bond using water. In this case, the magnesium-carbon bond is broken by treating the reaction mixture with water. This results in the formation of a tertiary alcohol.
- A tertiary alcohol is an alcohol in which the carbon atom attached to the hydroxyl group is attached to three other carbon atoms. In this case, the carbon atom attached to the hydroxyl group is the same carbon atom that was attached to the magnesium atom in the Grignard reagent (i.e., the carbon atom in the ethyl group).
- Therefore, the final product obtained after hydrolysis of the Grignard reagent is a tertiary alcohol.

Conclusion:

The correct answer is option D, i.e., tertiary alcohol.