In Kjeldahl's method, 29.5 mg of an organic compound containing nitrogen was digested and the evolved ammonia was absorbed in 20 mL of 0.1 N HCl solution. The excess of the acid required 15 mL of 0.1 N NaOH solution for complete neutralization. The percentage of nitrogen in the compound is

Options

A. 29.5
B. `59.0`
C. 47.4
D. 23.7

Answer

D

Explanation

Weight of substance taken `=29.5 xx 10^(-3)` g, Volume of acid taken=20 mL of 0.1 NHCI
Now, 15 mL of 0.1 N NaOH = 15 mL of 0.1 N HCI
Volume of acid used=20-15= 5 mL of 0.1 NHCl
% Nitrogen = `(1.4 xx "Volume" xx "Normality")/("Weight of substance taken") xx100 = (1.4xx5xx10^(-3) L xx1gL^(-1))/(29.5xx10^(-3)g)xx100 = 23.73 %`