When the pressure is increased,

Options

A. melting point of ice decreases and boiling point of water increases.
B. melting point of ice and boiling point of water decreases.
C. melting point of ice and boiling point of water increases.
D. melting point of ice increases and boiling point of water decreases.

Answer

**Step-by-Step Solution:**

1. **Understanding the Effect of Pressure on Boiling Point**:
- When pressure is increased, the boiling point of a liquid also increases. This is because boiling occurs when the vapor pressure of the liquid equals the external pressure. Higher pressure means that the liquid must reach a higher temperature to boil.

2. **Boiling Point of Water**:
- Under normal atmospheric pressure (1 atm), the boiling point of water is 100°C. However, if the pressure is increased, the boiling point will rise above 100°C. For example, at 1.5 atm, the boiling point of water might be around 110°C.

3. **Melting Point of Ice**:
- Conversely, the melting point of ice is affected differently by pressure. Generally, increasing pressure lowers the melting point of ice. This is due to the fact that ice is less dense than liquid water, so applying pressure favors the formation of liquid water over solid ice.

4. **Conclusion**:
- Therefore, when pressure is increased, the boiling point of water increases, and the melting point of ice decreases.

5. **Identifying the Correct Option**:
- Based on the effects of pressure on boiling and melting points, we can conclude that the correct option states that the melting point of ice decreases while the boiling point of water increases.

**Final Answer**: Option A is correct: The melting point of ice decreases and the boiling point of water increases.

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