Question

how does impurities affect the boiling point of a liquid

Answer 1

Hi,

Impurities in a substance would likely be of different elements and have different atomic/molecular structure than the substance. Different elements have different m.ps and b.ps. Using kinetic theory, as the substance heats up, the molecules will vibrate until they obtain sufficient energy (at b.p) to break free of their bonds/structure and move into gaseous state. Impurities, having a different b.p. (either higher or lower) will bump into these molecules and zap some of their kinetic energy away, hence, more energy is required, and thus the b.p. for the impure substance is increased.