The vapour pressure of water at `20^(@)` is `17.5 mmHg`. If `18 g` of glucose `(C_(6)H_(12)O_(6))` is added to `178.2 g` of water at `20^(@) C`, the vapour pressure of the resulting solution will be

Options

A. 15.750 mm Hg
B. 16.500 mm Hg
C. 17.325 mm Hg
D. 17.65 mm Hg

Answer

C

Explanation

`(P^(@)-P_(s))/(P^(@))=(n)/(n+N)`
`n=(18)/(180)=0.1, N=(178.2)/(18)=9.9`
`(17.5-p_(s))/(17.5)=(0.1)/(0.1+9.9),(17.5-p_(s))/(17.5)=(1)/(100)`
`1750-100 p_(s)=17.5 , 1732.5=100 p_(s)`
`p_(s)=17.325` mm Hg.