JEE Main 2014 · 6 Apr · Shift 1 · Chemistry Q32

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ChemistrySingle correct+4 / -1Question 32 of 90

If Z is a compressibility factor, van der Waals equation at low pressure can be written as :

Z=1+\dfrac{RT}{Pb}

Z=1-\dfrac{a}{VRT}

Z=1-\dfrac{Pb}{RT}

Z=1+\dfrac{Pb}{RT}

Answer and worked solution

Official answer: B

At low pressure the volume is large, so $b$ is negligible next to $V$ : $\left(P+\frac a{V^2}\right)V=RT$ . This gives $PV=RT-\frac aV$ , so
$Z=\frac{PV}{RT}=1-\frac a{VRT}.$

Topics:Real gases and van der Waals equation

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JEE Main 2014 · 6 Apr · Shift 1, Chemistry question 32