### Organic Chemistry Some Basic Principles and Techniques - Result Question 46

####52. In the Kjeldahl’s method for estimation of nitrogen present in a soil sample, ammonia evolved from $0.75 g$ of sample neutralized $10 mL$ of $1 M H_2 SO_4$. The percentage of nitrogen in the soil is :

(a) 37.33

(b) 45.33

(c) 35.33

(d) 43.33

[2014]

## Show Answer

#### Solution:

(a) $10 mL, 1 M H_2 SO_4=20 mL, 1 MNH_3$

$\because \quad$ wt of $N$ in one mole $NH_3=14$

$\therefore 20 \times 10^{-3} mol NH_3 \longrightarrow$

$ 20 \times 10^{-3} \times 14 \text{ nitrogen } $

$\therefore \quad 0.75 g$ of sample contains

$ =\frac{14 \times 20 \times 10^{-3}}{0.75} \times 100=37.33 % $