Q.What is Sublimation ?

Sublimation is the direct conversion of a substance from the solid state to the gaseous (vapour) state, without passing through the intermediate liquid state (and the corresponding reverse process, gas to solid directly, is called deposition or desublimation).

Normally, a solid must first melt into a liquid, which then vaporizes into a gas, as it is heated. However, some substances possess a high enough vapour pressure in the solid state itself that, upon heating (or even at room temperature/pressure for some substances), they pass directly from solid to gas, bypassing the liquid phase altogether. This process is called sublimation.

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