Question

An azeotropic mixture of two liquids boils at a lower temperature than either of them when ______.

Options

• it is saturated.

• it does not deviate from Raoult’s law.

• it shows negative deviation from Raoult’s law.

• it shows positive deviation from Raoult’s law.

Answer 1

An azeotropic mixture of two liquids boils at a lower temperature than either of them when it shows positive deviation from Raoult’s law.

Explanation:

Intermolecular forces between solute and solvent are weaker than interactions between solute and solvent when a solution deviates from Raoult’s law. The total vapour pressure of the solution is greater than the total vapour pressure of an ideal solution. Furthermore, each component’s vapour pressure is greater than expected under Raoult’s law. As a result, the azeotropic mixture of two liquids boils at a lower temperature than either liquid alone.