In Duma's method for estimation of nitrogen, 0.25
g of an organic compound gave 40 mL of nitrogen
collected at 300 K temperature and 725 mm pressure.
If the aqueous tension at 300 K is 25 mm, the
percentage of nitrogen in the compound is :-
- 18.20
- 16.76
- 15.76
- 17.36
- Explanation:
Volume of nitrogen collected at 300 K and 725 mm
pressure is 40 mL actual pressure
= 725 25 = 700 mm
Volume of nitrogen at STP
=273 × 700 × 40/300 × 760
33.52mL
22,400 mL of N2 at STP weight = 28 g
33.5 mL of nitrogen weight =
28×33.52/22400g
Percentage of nitrogen
28 × 33.52 × 100/22400 × 0.25
16.76%
