Question

A cylinder contains hydrogen gas at pressure of 249 kPa and temperature $27^\circ\,C$. Its density is :$(R = 8.3\,J\,mol^{-1}K^{-1}$)

• A. $0.5 \,kg/m^3$
• B. $0.2 \,kg/m^3$
• C. $0.1 \,kg/m^3$
• D. $0.02 \,kg/m^3$

Answer 1

The Correct Option is B

We can express, an ideal gas equation as $\frac{P}{\rho}=\frac{R.T}{Mw}$ $\Rightarrow \rho=\frac{pMw}{RT}$ $=\frac{249 \times 10^{3}\times 2 \times 10^{-3}}{8.314 \times 300}$ $=0.199$ $\Rightarrow \rho=0.2 kg/m^{3}$