Two substances X and Y have many free surfaces. They are subjected to heating. After heating. X is converted to another state which has one free surface and Y is converted to another state which has no free surfaces. Comment on the nature of X and Y.

Explanation

X and Y are solids as they have many free surcaces. On heating X is converted to liquid state with one free surface. That means X undergoes melting. On heating Y is converted to gaseous state with no free surfaces. That means Y undergoes submiation X is a normal solid whereas Y is sublimable solid.