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: ( Kb for CHCl3 = 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: ΔTb = 0.323 K w = weight of Anthracene. W = weight of chloroform

Kb = Molal elevation constant (3.9 K-kg/mol)

m=Kb×w×1000W×ΔTb=3.9×0.5143×10000.323×35

=177.42g/mol



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