A cylinder contains hydrogen gas at pressure of 249 kPa and temperature 27^{\circ} C. Its density is : \left( R =8.3 J mol ^{-1} K ^{-1}\right)
(1) 0.1 kg / m ^{3} (2) 0.02 kg / m ^{3} (3) 0.5 kg / m ^{3} (4) 0.2 kg / m ^{3}
A cylinder contains hydrogen gas at pressure of 249 kPa and temperature 27^{\circ} C. Its density is : \left( R =8.3 J mol ^{-1} K ^{-1}\right)
(1) 0.1 kg / m ^{3} (2) 0.02 kg / m ^{3} (3) 0.5 kg / m ^{3} (4) 0.2 kg / m ^{3}

Correct option: 4)

Using the ideal gas equation, we evaluate the value of density by making modification,

    \[\begin{aligned} &\therefore PV = nRT \\ &\Rightarrow PV =\frac{ m }{ M } RT \quad \therefore m =\rho V \\ & PV =\frac{(\rho V ) RT }{ M } \\ &\rho=\frac{ PM }{ RT } \Rightarrow \frac{249 \times 10^{3} \times 2 \times 10^{-3}}{8.3 \times 300} \Rightarrow 0.2 kg / m ^{3} \end{aligned}\]