6 g of a non volatil, non electrolyte X dissolved in 100g of water freezes at `-0.93^@C`. The molar mass of X in g `mol^(-1)` is `(K_f of H_2O=1.86kgmol^(-1))`.

Options

A. 60
B. 140
C. 180
D. 120

Answer

D

Explanation

`Delta T_(f) prop M`
`Delta T_(f)=K_(f)M=(K_f xx W xx 1000)/(M xx W^1)`.
`0.93 =(1.86 xx 6 xx 1000)/(0.93xx 100)=M=120`.