Question

An azeotropic solution of two liquids has a boiling point lower than either of them when it:

• A. is saturated
• B. shows positive deviation from Raoult’s law
• C. shows negative deviation from Raoult’s law
• D. shows no deviation from Raoult’s law

Hint:

A positive deviation from Raoult’s Law means that intermolecular forces in the mixture are weaker than in the pure components.

Answer 1

The Correct Option is B

An azeotropic mixture that has a boiling point lower than its components is called a minimum boiling azeotrope. This occurs when: - The intermolecular forces between different components are weaker than those in the pure liquids. - This results in a higher vapor pressure and, consequently, a lower boiling point than either of the individual components. - It occurs when the mixture exhibits a positive deviation from Raoult’s Law. Example: Ethanol-Water mixture (boiling point 78.2°C) boils at a lower temperature than pure ethanol or pure water.