EFFECT OF IMPURITIES ON SUBSTANCES

When substances are subjected to various temperatures they undergo change of state. The temperature at which melting occurs is referred to as melting point and the temperature at which boiling occurs is referred to as boiling point.

Impurities affect the melting point of a substance.
Effect of impurities on the melting point of naphthalene.Equal amounts of naphthalene and camphor are placed on a piece of paper and mixed thoroughly and placed in a boiling tube.

see the diagram below.