Question

For any substance, why does the
temperature remain constant
during the change of state?​

Answer 1

The temperature of any substance remain constant during the change of state because the heat energy supplied is used up in changing the state of matter and also this heat is used for breaking of several bonds or attractive forces. This heat, which does not raise the temperature of the body, is called Laten heat.

Answer 2

Because with the increase of temperature, more number of particles get enough kinetic energy to go into the vapour state. Hence temperature remains constant during the change of state.