Question

The boiling point of benzene is 353.23k.when 1.80 g of non voltile solute was dissolved in 90g of benzene the boiling point is raised to 354.11k calculate the molar mass of solute .Kb for benzene =2.53 kg/mol

Answer 1

Dear student ,
we know that ; m.w. of unknown solute = 1000$\times$ K_b $\times$w /W $\times$ $∆T$_b
and $∆T$_b = T_b - T₀ = 354.11 - 353.23 = 0.88 K
therefore m.m. = 1000 $\times$2.53 $\times$1.8 / 90 $\times$ 0.88
= 57.5 gm/mol