Question

Assertion :The increase in compressibility factor with increasing pressure is due to $a$. Reason: $Z=1+\frac{bP}{RT}$ for real gases can be obtained by neglecting $\frac{a}{V^2}$ term in van der Waal's equation.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Assertion is incorrect but Reason is correct

Answer 1

The correct option is D Assertion is incorrect but Reason is correct

At high pressure, the expression for the compressibility factor is $Z=1+\frac{bP}{RT}$.
Thus, the increase in compressibility factor with increasing pressure is due to $b$. Hence, the assertion is incorrect.
For real gases, the expression for the compressibility factor i.e $Z=1+\frac{bP}{RT}$ can be obtained when the term $\frac{a}{V^2}$ in the van der Waal's equation is neglected.
Thus, the reason is correct.