Question

A vessel of volume $0.02m^3$ contains a mixture of hydrogen and helium at $20C$ and 2 atmosphere pressure. The mass of mixture is 5.g. Find the ratio of mass of hydrogen to that of helium in the mixture.

• A. $1:2$
• B. $1:3$
• C. $2:3$
• D. $3:2$

Answer 1

The correct option is A $1:2$

From ideal gas equation, PV=nRT

Here, assume the mass of helium in the mixture is x, then the mass of hydrogen is (5−x).

Applying ideal gas equation,

$2\times {10}^5\times 0.02$ = $(\frac{5-x}{2}+\frac{x}{4})$$\times 8.314\times 293$

$x$ =3.43 and $5-x$=1.57.

So, the ratio of hydrogen to helium is 1 : 2.

Hence, option A is correct.