At `100^(@)C` the vapour pressure of a solution of 6.5 gm of a solute in 100 g water is 732 mm. If `K_(b)=0.52`, the boiling point of this solution will be :

Options

A. `100^(@)C`
B. `102^(@)C`
C. `103^(@)C`
D. `101^(@)C`

Answer

D

Explanation

`(P_(1)^(0)-P_(1))/(P_(1)^(0))=(n_(2))/(n_(1))`
`(760-732)/(760)=(6.5xx18)/(M_(2)xx100) " " therefore M_(2)=31.6`
`Delta T_(b)=(0.52xx6.5xx1000)/(31.6xx100)=1.07`
`therefore` Vapour pressure `= 100+1.07`
`= 101.07^(@)C`
`~~101^(@)C`