The depression in freezing point is maximum if the solvent used is

Options

A. Camphor
B. Naphthalene
C. Benzene
D. Water

Explanation

To solve the question regarding which solvent has the maximum depression in freezing point, we will follow these steps:

### Step-by-Step Solution:

1. **Understanding Depression in Freezing Point**:
- The depression in freezing point occurs when a non-volatile solute is added to a solvent, resulting in a decrease in the freezing point of the solvent. This phenomenon is quantified by the formula:
\[ \Delta T_f = K_f \times m \]
- Where:
- \(\Delta T_f\) = depression in freezing point
- \(K_f\) = cryoscopic constant (freezing point depression constant) of the solvent
- \(m\) = molality of the solution

2. **Identify the Solvents and Their \(K_f\) Values**:
- We need to compare the \(K_f\) values of the given solvents:
- **Camphor**: \(K_f = 37.7 \, \text{°C kg/mol}\)
- **Naphthalene**: \(K_f = 6.94 \, \text{°C kg/mol}\)
- **Benzene**: \(K_f = 5.12 \, \text{°C kg/mol}\)
- **Water**: \(K_f = 1.86 \, \text{°C kg/mol}\)

3. **Comparing the \(K_f\) Values**:
- From the values listed:
- Camphor has the highest \(K_f\) value (37.7).
- Naphthalene has a \(K_f\) of 6.94.
- Benzene has a \(K_f\) of 5.12.
- Water has the lowest \(K_f\) of 1.86.

4. **Conclusion**:
- Since the depression in freezing point (\(\Delta T_f\)) is directly proportional to the \(K_f\) value, the solvent with the highest \(K_f\) will have the maximum depression in freezing point.
- Therefore, **Camphor** has the maximum depression in freezing point among the given solvents.

### Final Answer:
The depression in freezing point is maximum if the solvent used is **Camphor**.

---