At `35 ""^(@)C` the vapour pressure of `CS_(2)` is 512 mm of Hg and that of acetone is 344 mm of Hg. A solution of `CS_(2)` in acetone has a total vapour pressure of 600 mm of Hg. The false statement among the following is :

Options

A. `CS_(2)` and acetone are less attracted to each other than themselves.
B. Heat must be absorbed in order to produce the solution at `35^(@)C`.
C. Raoult's law is not obeyed by this system
D. A mixture of 100 mL `CS_(2)` and 100 mL acetone has a volume less than 200 mL.

Answer

D

Explanation

`p_("total")=p_(A)^(@)x_(A)+p_(B)^(@)x_(B)`
Maximum value of `X_(A)` is 1, so `p_("total")` has maximum value of 512 mm, which is less value than observed 600 mm value, so positive deviation would be observed. In which interaction between A-A and B-B is more than A-B interaction.
So, for the system which does not follow Raoult.s law and shows positive deviation,
`Delta V_(mix)gt 0, Delta H_(mix)gt 0`