Equal weights of two gases of molecular weight 4 and 40 are mixed. The pressure of the mixture is 1.1 atm. The partial pressure of the light gas in this mixture is

Options

A. 0.55 atm
B. 0.11 atm
C. 1 atm
D. 0.12 atm

Answer

C

Explanation

Total no. of moles =` m/4 + (m)/(40) = (11m)/(40)`
Mole fraction of lighter gas = (m/4)/((11m)/(40)) = 10/11`
Partial pressure due to lighter gas = `P_0 xx 10/11`
` = 1.1 xx 10/11 = 1 atm`