Concept:Non-ideal solutions can show positive or negative deviations from Raoult's law, affecting vapour pressure in different ways.
Explanation:Statement A is true because an ideal solution obeys Raoult's law over the entire range of temperature and concentration.
Statement B is true because for an ideal solution,
ΔmixV=0.
Statement C is true because a non-ideal solution does not obey Raoult's law over the entire range of concentration.
Statement D is false.
For a non-ideal solution, the vapour pressure does not always lie between the vapour pressures of the pure components.
In a positive deviation, solute–solvent interactions are weaker than pure component interactions, so the vapour pressure becomes higher than the ideal value and may exceed the vapour pressures of both pure components.
In a negative deviation, solute–solvent interactions are stronger, so the vapour pressure becomes lower than the ideal value and may fall below the vapour pressures of both pure components.
Therefore, the vapour pressure of a non-ideal solution can lie outside the range of the pure component vapour pressures.
Answer:The false statement is Option D: "Vapour pressure of non-ideal solution always lies between vapour pressure of pure components."