Question

A sample of 0.125 g of an organic compound when analyzed by Duma's method yields 22. 78 mL of nitrogen gas collected over KOH solution at 280 K and 759 mm Hg. The perentage of nitrogen in the given organic compound is ______. (Nearest integer)

Given:

1. The vapour pressure of water of 280 K is 14.2 mm Hg.
2. R = 0.082  L atm K^-1 mol^-1 

Options

• 69

• 22

• 32

• 10

Answer 1

A sample of 0.125 g of an organic compound when analyzed by Duma's method yields 22. 78 mL of nitrogen gas collected over KOH solution at 280 K and 759 mm Hg. The perentage of nitrogen in the given organic compound is 22.

Explanation:

V = 22.78 mL, T = 280 K

P_total = 759 mmHg

`"P"_("N"_2)` = 759 - 14.2 = 744.8 mmHg

`"n"_("N"_2) = (744.8 xx 22.78)/(760 xx 1000 xx 0.082 xx 280)` = 0.00097

`"W"_"Nitrogen" = 0.02716`

%N = `("Wt. of N")/("Wt. of sample") = 0.02716/0.125 xx 1000 = 21.728`