Sublimation is the process of changing a substance from the solid state directly into the gaseous state. It doesn’t form the liquid state before converting to the gaseous state.
For example, if you heat solid dry ice, it changes into the gaseous state.
Examples of substances that can undergo sublimation process are
1. Dry ice (solid carbon dioxide)
2. Ammonium chloride (it doesn’t really sublimes. Its a chemical reaction that is reversible upon heating)
6. Mercuric Chloride
Sublimation is also used to describe a method used to separate mixtures containing substances that sublimes.
For example, to separate a mixture of iodine and sand, we can use sublimation to separate the iodine from the salt. When we heat the mixture, the iodine sublimes and became gaseous state leaving the sand behind. To collect the iodine back in the form of solid, we can place a filter funnel above the mixture. The gaseous iodine when touches the filter funnel will change back to the solid state.