The vapour pressure of a solution prepared by dissolving 1 mol of liquid A and 2 mol of liquid B has been found to be 38 torr. The vapour pressure of pure A and pure B are 45 and 36 torr respectively. The solution

Options

A. shows negative deviation
B. is a minimum boiling azeotrope
C. is an ideal solution
D. has A Hmixing positive

Answer

A

Explanation

According to Raoult.s law .
`p_(A) = x_(A) p_(A)^(@) = (1)/(3) xx 45 = 15` torr
`p_(B) = x_(B) p_(B)^(0) = (2)/(3) xx 36 = 24` torr
Total pressure = 15+24=39 torr
The observed pressure is less than expected value and hence it shows negative deviation.