Sprinkling of salt helps in clearing the snow covered roads in hills. The phenomenon involved in the process is:

Options

A. Lowering in vapour pressure of snow
B. Depression in freezing point of snow
C. Melting of ice due to increase in temperature by putting salt
D. Increase in freezing point of snow

Explanation

To solve the question regarding why sprinkling salt helps in clearing snow-covered roads in hills, we need to understand the underlying phenomenon.

### Step-by-Step Solution:

1. **Understanding Freezing Point Depression**:
- When salt (NaCl) is sprinkled on snow, it acts as a non-volatile solute. The presence of this solute affects the freezing point of water (the main component of snow).

2. **Effect of Salt on Freezing Point**:
- The addition of salt to ice (or snow) lowers the freezing point of water. This means that the ice will start to melt at a lower temperature than it normally would.

3. **Vapor Pressure Consideration**:
- In pure water, there is a specific temperature at which it freezes (0°C). However, when salt is added, the vapor pressure of the solution decreases compared to that of pure water.

4. **Graphical Representation**:
- If we were to plot a vapor pressure vs. temperature curve, we would see that the curve representing the freezing point of pure water intersects with the curve of the salt solution at a lower temperature. This intersection point indicates the new freezing point.

5. **Conclusion**:
- Therefore, the phenomenon involved in the process of using salt to clear snow is known as **depression in freezing point**. This is the reason why roads can be cleared of snow even when the temperature is below the normal freezing point of water.

### Final Answer:
The phenomenon involved in the process is **depression in freezing point of snow**.

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