1.0 g of non - electrolyte solute dissolved in 50 g of benzene lowered the freezing point of benzene by 0.4 K. Find the molar mass of the solute. [Given : Freezing point depression constant of benzene = 5.12 K. kg mol].

Explanation

Given ,
`W_(2)= 1.00 g , W_(1) = 50 ` g
`K_(f) = 5.12 K " kg mol"^(-1)`
` Delta T_(f) = (K_(f) xx w_(2) xx 1000 )/(M_(2) xx W_(1) ) `
`M_(2) = (K_(f) xx W_(2) xx 1000)/(W_(1) xx Delta T_(f))`
= `(5.12 xx 1 xx 1000)/(50 xx 0.40)`
`M_(2) = 256 g " mol "^(-1)`