Answer:
Sublimation.
Explanation:
Sublimation may be defined as one of the technique used for the separation of substances from the mixtures of substances. Two solid impurities can be separated by this technique.
The substance is directly changed from the solid phase to the gas phase in sublimation and vice-versa. The liquid state is not involved in the conversion of solid into the gaseous state in case of sublimation.
Thus, the answer is sublimation.
