Question

A vessel of volume 20L contains a mixture of hydrogen and helium at temperature 27^∘C and pressure 2atm. The total mass of the mixture is 5g. Assuming ideal gases, the ratio of mass of hydrogen to that of helium is 

• A. \(1:2\)
• B. \(2:3\)
• C. \(2:1\)
• D. 2:5

Hint:

For gas mixtures: 

• Use molar mass carefully. 

• Partial moles determine mass ratios.

Answer 1

The Correct Option is B

Step 1: Let masses be mH and mHe.
Step 2: Using ideal gas law and molar masses: (mH)/(2) + fracmHe4 = constant
Step 3: Using total mass mH + mHe = 5, solving gives: mH : mHe = 2 : 3