Question

What is meant by positive and negative deviations from Raoult's law and how is the sign of Δ$_{mix}$H related to positive and negative deviations from Raoult's law?

Answer 1

Hey Dear,

◆ Raoult's law -

• Raoult's law states that the mole fraction of the solute component is directly proportional to its partial pressure.

# Positive deviation from Raoult's law -

• Solutions which show higher than expected vapour pressures are said to show positive deviation from Raoult's law.
• For these solutions, ∆mixH = positive

# Negative deviation from Raoult's law -

• Solutions which show lower than expected vapour pressures are said to show negative deviation from Raoult's law.
• For these solutions, ∆mixH = negative

Thanks dear..