Question

$1.2\mathrm{g}$ of an organic compound on Kjeldahl method liberates ammonia which consumes $30c{m}^3$ of $1\mathrm{N}$ $\mathrm{HCl}$. The percentage of nitrogen in the organic compound is?

Answer 1

Step 1: Given data

Weight of the organic compound (w) =$1.2\mathrm{g}$

Amount of ammonia consumed = $30c{m}^3=30ml$

Normality of $\mathrm{HCl}$ = $1\mathrm{N}$

Step 2: Formula used

The percentage of Nitrogen evolved can be calculated using the formula:

$\frac{1.4\times N\times V\left(ml\right)}{w\left(gm\right)}$

where, $\mathrm{N}$ is the normality of the acid

$\mathrm{V}$ is the volume of ammonia

$\mathrm{w}$ is the weight of the organic compound

Step 3: Calculate the percentage of Nitrogen.

Put the given values in the formula to calculate the percentage of nitrogen in the organic compound.

$\%ofN=\frac{1.4\times 1\times 30}{1.2}=35\%$

Hence, the percentage of nitrogen in the organic compound is $35\%$.