In which of the following reactions of alcohol there is no cleavage of C-O bond ?

Options

A. `ROH + PCI_(5)`
B. `ROH + SOCI_(2)`
C. ROH + HCI
D. ROH + Na

Answer

To determine which reaction of alcohol does not involve the cleavage of the C-O bond, let's analyze each option step by step.

### Step-by-Step Solution:

1. **Identify the Reactions**: We have four reactions involving alcohols. We need to analyze each one to see if the C-O bond is broken.

2. **Reaction with PCl5**:
- **Reaction**: ROH + PCl5 → RCl + POCl3 + HCl
- **Analysis**: In this reaction, the C-O bond is cleaved as the alcohol (ROH) is converted into an alkyl chloride (RCl). Therefore, this reaction involves cleavage of the C-O bond.

3. **Reaction with SO2Cl2 (Thionyl Chloride)**:
- **Reaction**: ROH + SO2Cl2 → RCl + SO2 + HCl
- **Analysis**: Similar to the first reaction, the C-O bond is also cleaved here as the alcohol is converted into an alkyl chloride. Thus, this reaction also involves cleavage of the C-O bond.

4. **Reaction with HCl**:
- **Reaction**: ROH + HCl → RCl + H2O
- **Analysis**: In this case, the alcohol reacts with HCl, and the C-O bond is cleaved to form an alkyl chloride. Therefore, this reaction also involves cleavage of the C-O bond.

5. **Reaction with Sodium (Na)**:
- **Reaction**: ROH + Na → R-O^-Na^+ + H2
- **Analysis**: Here, sodium reacts with the alcohol to form an alkoxide ion (R-O^-) and hydrogen gas (H2). Importantly, the C-O bond remains intact in this reaction, as only the hydrogen atom is removed from the alcohol.

### Conclusion:
The only reaction in which there is no cleavage of the C-O bond is the reaction of alcohol with sodium (Na). Therefore, the correct answer is **D**.