Matter in Our Surroundings — Science STD 9 — Question

1. When a solid substance converts directly into gas without going through the liquid phase it is called Sublimation.
2. On the contrary when gas directly forms into solid omitting the intermediate stage of liquefying it is called deposition or desublimation.

Sublimation is an endothermic process, where as Desublimation is a thermodynamic process.