Question

If the gas 'X' behaves ideally, then the pressure P of gas at ${27}^{o}C$ is :

• A. $12.32$ atm
• B. $24.63$ atm
• C. $1$ atm
• D. $6.15$ atm

Answer 1

The correct option is B $24.63$ atm

Given,
$C_p=0.125cal/g,C_v=0.075cal/g$

Also as we know,

$C_p-C_v=\frac{R}{M}$

$M=\frac{2}{0.125-0.075}=40$

Also, $\frac{C_p}{C_v}=\frac{0.125}{0.075}=\frac{5}{3}=1.66$, so gas is monoatomic, also molar mass of gas is 40 so gas is Ar.

and according to ideal gas equation

$PV=nRT(n=\frac{w}{M}=\frac{200}{40}=5)$

$P\times 5=\frac{200}{40}\times 0.0821\times 300$

$P=24.63$ atm.