An ideal solution of two liquids is a solution in which each component obeys Raoult's which states that the vapour pressure of any component in the solution depends on the mole fraction of that component in the solution and the vapour pressure of that component in the pure state. However, there are many solution which do not obey Raoult's law. In other words, they show deviations from ideal behaviour which may be positive or negative. However, in either case, corresponding to a particular composition, they form a constant boiling mixtures called azeotropes.
Which of the following mixture do you expect will not show positive deviation from Raoult's law ?

Options

A. shows no deviations from Raoult's law
B. shows a positive deviation from Raoult's law
C. shows a negative deviation from Raoult's law
D. is staurated

Answer

B

Explanation

Lower boiling point means higher vapour pressure than expected which implies positive deviation.