Question

During the estimation of nitrogen present in an organic compound by Kjeldahl's method, the ammonia evolved from $0.5g$ of the compound in kjeldahls estimation of nitrogen, neutralized $10mL$ of $1M$ $H_2{SO}_4$. Find out the percentage of nitrogen in the compound.

Answer 1

Mass of organic compound= $0.5g$

Volume of $1M$ $H_{2}S{O}_4$ required= $10ml$

$\therefore 10ml$ of $1M$ $H_{2}S{O}_4=20ml$ of $1M$ $N{H}_3$

Now $1000ml$ of $1M$ $N{H}_3$ contains $14g$ $N$

$\therefore 20ml$ of $1M$ $N{H}_3$ would contain= $\frac{14}{1000}\times 20$

$\therefore$ Percentage of $N=\frac{14\times 20}{1000}\times \frac{100}{0.5}=56$%