In Dumas' method for estimation of nitrogen, 0.5 gram of an organic compound gave 60 mL of nitrogen collected at 300 K temperature and 715 mm Hg pressure. The percentage composition of nitrogen in the compound (Aqueous tension at 300 K = 15 mm Hg) is %.
- 20.87
- 12.57
- 1.257
- 18.67
Answer
(2) 12.57
Solution
Pressure of dry nitrogen = 715 - 15 = 700 mm Hg
Volume of N2 at STP: V0 = P1V1T1 T0P0
V0 = 700 60 273300 760
V0 = 50.29 mL
22400 mL of N2 at STP weighs 28 g
% N = 28 V0 10022400 m
% N = 28 50.29 10022400 0.5
% N = 12.57
Answer: (2)