Tamil Nadu Board of Secondary EducationSSLC (English Medium) Class 9

Methods of Separation - Sublimation Method




Sublimation Method:

Sublimation in chemistry refers to the phase transition in which matter changes state from a solid immediately into a gas, without passing through an intermediate liquid phase. Sublimation occurs when atmospheric pressure is too low for a substance to exist in liquid form. Sublimation is the inverse of deposition, the phase transition in which gas goes immediately to a solid state. Whether or not a substance will sublimate from a solid to a gaseous state depends on the triple point of the substance, the temperature and pressure at which a substance exists in equilibrium as the three states of matter.

A substance will only sublimate at temperatures and pressures lower than the substance’s triple point.


  • Used in air freshener solids


Experiment of the separation of ammonium chloride and salt by sublimation.

Aim: To check sublimation.

Requirements: Salt, ammonium chloride, inverted funnel, china dish, cotton plug, burner.


  • Take some mixture of salt and ammonium chloride.
  • Put an inverted funnel over the china dish.
  • Put a cotton plug on the stem of the funnel.
  • Now, heat slowly and observe.

Observation: Ammonium chloride on heating, was evaporated and salt was left behind.

Result/ Inference: Ammonium chloride changed its state directly from solid to gas without changing into a liquid state. Hence, salt got separated.

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