Question

The density of a gas at normal pressure and $27^{o}C$ temperature is $24$ units. Keeping the pressure constant, the density at $127^{o}C$ in same units will be

• A. $6$
• B. $12$
• C. $18$
• D. $24$

Answer 1

Answer: (C)

Pressure is $P=\frac{\rho R T}{M}$
Hence at constant pressure, $\rho T=$ constant
$\Rightarrow \frac{\rho _{1}}{\rho _{2}}=\frac{T_{1}}{T_{2}}$
$\Rightarrow \frac{24}{\left(\rho \right)_{2}}=\frac{\left(273 + 127\right)}{\left(273 + 27\right)}=\frac{400}{300}$
$\Rightarrow p_{2}=18 \, units$