Question

In the estimation of nitrogen by Kjeldahl's method, $2.8g$ for an organic compound required $20$ millimoles of $H_{2}S{O}_4$ for the complete neutralization of $N{H}_3$ gas evolved. The percentage of nitrogen in the sample is:

• A. $20\%$
• B. $10\%$
• C. $40\%$
• D. $30\%$

Answer 1

The correct option is A $20\%$

$\%$ of $N=\frac{1.4\times mEqof{H}_{2}S{O}_{4}usedtoneutralizeN{H}_3}{Weightofcompound}$

mmoles of $H_{2}S{O}_4=20$ (Given)

mEq. of $H_{2}S{O}_4=20\times 2=40$ ($n$ factor $=2$)

$\%$ of $N=\frac{1.4\times 40}{2.8}=20\%$