Question

Explain why temperature remain constant during interconversion of three state of matter

Answer 1

When the state of a substance changes, then the temperature of the substance remains constant because the heat that is supplied gets used up for overcoming and weakening the particle-particle attraction force, which changes the state of the system. The substance thus absorbs heat energy without showing any rise in temperature.
For example, a solid melts on heating. Its temperature does not rise until the entire solid is converted into liquid. Similarly, on heating a liquid changes into the vapour state and its temperature does not rise until the entire liquid changes into vapour state

Answer 2

This is because the heat supplied to the substance is used up in overcoming the intermolecular forces between the particles