Question

Find the percentage of nitrogen in an organic compound analysed by Kjeldahl method $1.61$ g of the compound produced $N{H}_3$ which was absorbed in $250$mL of $\frac{N}{2}{H}_{2}S{O}_4$ solution. The remaining acid was then diluted to one litre, $25$mL of which required $25.5$mL of $N/10$ $NaOH$ for exact neutralization.

Answer 1

% of $N_2$ by Kjeldlal's method $=\frac{1.4\times M\times 2\times \left(\frac{V-V_1}{2}\right)}{Massoforganiccompound}$

$V=$ Vol. of $H_2{SO}_4=250$ml

$V_1=$ Vol. of $NaOH=25.5$ml

$\frac{N}{2}{H}_2{SO}_4=\frac{M}{4}{H}_2{SO}_4(\because n=2)$

Mass of $0.6=1.619$

% $N_2=1.4\times \frac{1}{4}\times 2\left(\frac{250-\frac{25.5}{2}}{1.61}\right)\approx 49.0217$%