Question

The melting point of ice ______ when pressure increases.

• A. Increases
• B. Decreases
• C. Remains same
• D. None of these

Answer 1

The correct option is B

Decreases

The explanation for the correct option:

In the case of option B,

1. The melting point of a substance is the temperature at which it converts from its solid state to its liquid state.
2. There is no change in the temperature of a substance, as all the heat supplied at the melting point is used in the conversion of the state of the substance.
3. According to Boyle's law, $PV=cons\tan t$, where $P$ is pressure and $V$ is volume. Thus, $P\propto \frac{1}{V}$.
4. So, when pressure increases, volume decreases.
5. The melting point of ice decreases when pressure increases because when pressure is increased volume is decreased and the volume of water is less than ice
6. So it will be easier to change the state from solid to liquid, and therefore, the melting point decreases.

The explanation for the incorrect options:

In the case of option A,

1. The melting point of ice decreases when pressure increases.
2. Thus, this option is incorrect.

In the case of option C,

1. The melting point of ice decreases when pressure increases.
2. Thus, this option is incorrect.

In the case of option D,

1. Since option B is correct, this option is incorrect.

Hence, option B is correct.