Boiling point of chloroform was raised by 0.323 K, when 0.5143 g of anthracene was dissolved in 35 g of chloroform. Molecular mass of anthracene is 

${\text{(K}}_{\mathrm{b}} \mathrm{for} {\mathrm{CHCl}}_3=3.9 \mathrm{K}. \mathrm{kg} {\mathrm{mol}}^{-1})$