Solutions Question 52

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-1) [Pb PMT 2000]

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}=0.323K $

$ w=0.5143g $ weight of Anthracene. $ W=35g $ weight of chloroform $ K_{b}= $ Molal elevation constant $ (3.9K-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 $



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