Concentrated nitric acid oxidises phosphorus to phosphoric acid according to the following equation:
P+5HNO3→H3PO4+5NO2+H2O
If 6.2 g of phosphorus was used in the reaction, calculate:
(a) The number of moles of phosphorus taken and mass of phosphoric acid formed.
(b) Mass of nitric acid consumed at the same time.
(c) The volume of steam produced at the same time if measured at 760 mm Hg pressure and 273∘C.
Volume is directly proportional to temperature at constant pressure(charles law).
(a) 1 mol of phosphorus forms 1 mol of phosphoric acid. Thus 0.2 mol of phosphorus will form 0.2 mol of phosphoric acid.
1 mol of phosphoric acid = (3 + 31 + 64) g = 98 g
0.2 mol of phosphoric acid = 98×0.2 = 49 g