Solutions Question 403

Question: 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: ( $ K_{b} $ for $ CHCl_3 $ = 3.9 kg/mol )

Options:

A) 79.42 g/mol

B) 132.32 g/mol

C) 177.42 g/mol

D) 242.32 g/mol

Show Answer

Answer:

Correct Answer: C

Solution:

Here: $ \Delta T_{b} $ = 0.323 K w = weight of Anthracene. W = weight of chloroform

$ K_{b} $ = Molal elevation constant (3.9 K-kg/mol)

$ m=\frac{K_{b}\times w\times 1000}{W\times \Delta T_{b}}=\frac{3.9\times 0.5143\times 1000}{0.323\times 35} $

$ =177.42g/mol $



NCERT Chapter Video Solution

Dual Pane