Question

State the effect of an increase of pressure on the melting point of ice.

Answer 1

Hint When a substance is in its solid state, the molecules of the substance will be closely packed. When the substance is heated, the molecules will move away from each other. Ice is in its solid-state and on heating, it will be converted into water.

Complete Step by step solution
Since the pressure of a substance is acting from outside, it is an external factor. The change in external factors can affect the equilibrium of the system. This change in external factors will disrupt the equilibrium of the system.
According to LeChatelier’s principle,
For a system is in equilibrium for a prolonged period, the change in external factors like temperature, pressure, concentration, volume, etc. will disrupt the equilibrium of the system and the system will attain a new equilibrium. This will counteract the external change applied.
Therefore, when we increase the pressure on ice, the equilibrium point for the system of ice and water will be lowered. Ice will occupy more space than water. That is, water requires a lesser volume than that of ice. When the pressure is increased, the volume decreases forcing more ice to become water to fit in the reduced volume. This means that when the pressure is increased the melting point of water will be lowered further to enable more ice to melt into water.

Additional information
This property is utilized by skaters when they skate through the ice. The pressure due to their weight will cause the ice to melt and they can glide smoothly through the ice.

Note
The melting point of a substance can be defined as the temperature at which phase transition happens from solid-state to liquid state. The temperature at which a substance changes its phase from liquid to solid is called the freezing point.