Acetone can be converted into pinacol by :

Options

A. `Mg//Hg//H_(2)O`
B. `Zn//Hg//HCl`
C. `Na//Hg//H_(2)SO_(4)`
D. all of these

Answer

To convert acetone into pinacol, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Starting Material**:
- The starting material is acetone, which has the structure \( CH_3C(=O)CH_3 \).

2. **Reagents Required**:
- The conversion of acetone to pinacol involves the use of magnesium amalgam (Mg) in the presence of water (H2O).

3. **Mechanism Overview**:
- This reaction is known as the pinacol rearrangement. It involves the formation of a radical intermediate.

4. **Formation of Radical**:
- When acetone reacts with magnesium, the double bond between carbon and oxygen in acetone shifts, resulting in a negative charge on the oxygen and a radical on the carbon. This occurs for both moles of acetone used in the reaction.

5. **Radical Coupling**:
- The radical formed on one carbon can couple with the radical formed on another carbon from the second molecule of acetone. This leads to the formation of a new carbon-carbon bond.

6. **Formation of Pinacol**:
- After the radical coupling, the intermediate product has two hydroxyl (OH) groups. When this intermediate reacts with water, the hydroxyl groups are formed at the respective positions, leading to the final product, pinacol.

7. **Final Product Structure**:
- The final structure of pinacol can be represented as:
\[ CH_3C(OH)(C(OH)CH_3) \]
- This shows that pinacol has two methyl groups and two hydroxyl groups attached to the same carbon atoms.

### Conclusion:
The correct reagent for converting acetone to pinacol is magnesium amalgam in the presence of water.