Maximum freezing point fall is

Options

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

Answer

To determine which substance has the maximum freezing point fall, we need to analyze the cryoscopic constants (Kf) of the given substances. The freezing point depression is directly proportional to the cryoscopic constant, which means that a higher Kf value corresponds to a larger freezing point depression.

### Step-by-Step Solution:

1. **Understand the Concept of Cryoscopic Constant (Kf)**:
- The cryoscopic constant (Kf) is a property of a solvent that indicates how much the freezing point of the solvent will decrease when a solute is added. The greater the Kf, the more significant the freezing point depression.

2. **List the Cryoscopic Constants for Each Substance**:
- Kampfer: Kf = 39.70°C
- Naphthalene: Kf = 6.94°C
- Benzene: Kf = 5.12°C
- Water: Kf = 1.860°C

3. **Compare the Kf Values**:
- From the values listed, we can see that Kampfer has the highest Kf value (39.70°C), followed by naphthalene (6.94°C), benzene (5.12°C), and water (1.860°C).

4. **Determine the Substance with Maximum Freezing Point Fall**:
- Since the freezing point depression is proportional to Kf, Kampfer, having the highest Kf, will experience the maximum freezing point fall when a solute is added.

5. **Conclusion**:
- Therefore, the correct answer to the question "Maximum freezing point fall is" is **Kampfer**.

### Final Answer:
The correct option is **A, Kampfer**.