Sublimation

Sublimation is used to separate a mixture of Solid and a Solid

What is Sublimation?

It is a process where a solid directly converts into its gas phase without going into liquid state .

Example

• Solids like Ammonium chloride, Naphthalene,Camphor and Anthracene undergo Sublimation.
• When we heat them they convert directly into gases without first converting into liquid

Hence, to separate a mixture having a sublimable and non-sublimable component , we use the method of sublimation.

How to Separate a Mixture of Salt and Camphor?

In a mixture of Salt and Camphor,

Camphor 

• Sublimes on heating
• Hence it is a sublimable component

Common salt (Sodium Chloride) 

• Does not undergo sublimation
• It is a non sublimable component.
  
  

Procedure

1. Take a mixture of salt and camphor in a china dish
2. Place an inverted funnel over it
3. Close the end of the funnel with a cotton plug
4. Now heat the mixture

On heating , camphor undergoes sublimation (converts into vapours)

These vapors solidify again on the surface of the funnel

However salt does not undergo sublimation and remains on the china dish