Vapour pressure of a solvent containing nonvolatile solute is:

Options

A. 103 mm Hg
B. 99 mm Hg
C. 97 mm Hg
D. 101 mm Hg

Answer

C

Explanation

For complete dissociaiton of electrolyte `AB_(2)`
`AB_(2) to A^(2+) + 2B^(-2) I = 3`
Relative lowering in vapour pressure ,
`(p^(@) - p)/(p^(@)) = ixx (n_(2))/(n_(1) + n_(2))`
`(100-p)/(100) = 3 xx (1)/(1+99)`
` 100- p = (3 xx 100)/(100) = 3 `
` therefore p = 100 - 3 = 97 mm Hg`