The density of a gas is 1.964 g dm-3 at 273 K and 76 cm Hg. The gas is (AFMC 2008)

Ideal gas equation, w pV nRT pV RT M >> w n M w RT RT M M d V p p >> >> Here, 3 3 1.964 / 1.964 10 / d g dm g cc x p = 76 cm = 1 atm R = 0.0821 L atm K-1 mol-1 or = 82.1 cc atm K-1 mol-1 T = 273 K 3 1.964 10 82.1 273 44 / 1 M g mol x x x The molecular weight of CO2 is 44 g mol-1. The gas is CO2.