The freezing point of a solution prepared from `1.25 g` of non-electrolyte and `20 g` of water is `271.9 K`. If the molar depression constant is `1.86 K mol^(-1)`, then molar mass of the solute will be

Options

A. 105.7
B. 106.7
C. 115.3
D. 93.9

Answer

A

Explanation

`M_(B)= ( W_(B)xxK_(f))/( W_(A) xx Delta T_(f))xx1000`
` =(1.25 xx 1.86 xx 1000)/( 20 (273 -271.9 ))`
` = ( 1.25 xx 1.86 xx 1000)/( 20 xx1.1)`