The process during which a solid directly changes into its gaseous state on heating is called sublimation. It is the process during which gas is directly changed into its solid state on cooling. A mixture of ammonium chloride and common salt is separated by sublimation and deposition.

The process during which gas is directly changed into its solid state on cooling is deposition. Deposition is the transition of a substance directly from the gas to the solid state on cooling, without passing through the liquid state. A mixture of ammonium chloride and common salt is separated by sublimation and deposition. Solid → sublimation ( heating ) Vapour Solid → Deposition ( cooling ) Vapour

The process during which a liquid changes into its vapour on heating (below the boiling point) is called evaporation. This method is used to separate the components of a homogeneous solid-liquid mixture because liquids vaporise easily whereas solids do not.