Question

A pressure in a vessel tht contained pure oxygen dropped from 2000 torr to 1500 torr in 40min.

Answer 1

Molar ratio of  a mixture of oxygen and another gas is 1 : 1 at a pressure 4000 mm,  

Partial pressure of each gas = 2000 mm Hg.

The decrease in the pressure of oxygen after 1 minutes

= 500/40 = 12.5 mmHg

The decrease in the pressure of oxygen after 74 minutes

P = 12.5 * 74 =  925 mm of Hg

The pressure of oxygen

= 2000 – 925 = 1075 mm of Hg

Let the rate of diffusion of other gas is

Rn / RO2 = (32 /79 )1/2

P = P0 * R^2

Decrease in pressure for the other gas =925 * 32/79

= 374.68 mm of Hg

Pressure of the other gas  

= 2000 – 374.68 mm = 1625.31 mm of Hg

Molar ratio = Moles of other gas/Moles of O2

= 1625.31/1075 = 1.51/1