Question

Assertion (A): At constant temperature, $PV$ vs $P$ plot for real gases is not a straight line.
Reason (R): At high pressure all gases have $Z>1$ but at intermediate pressure most gases have $Z<1$.

• A. Both A and R are true and R is the correct explanation of A.
• B. Both A and R are true but R is not the correct explanation of A.
• C. A is true but R is false.
• D. A is false but R is true.

Answer 1

The correct option is B Both A and R are true but R is not the correct explanation of A.

$PV$ versus $P$ plot is straight line for ideal gases but not for real gases as inter-molecular forces of attraction are present in real gases whose molecules have finite real sizes and we see deviation from ideal behavior. At high pressure, there is positive deviation from ideal behaviour $(Z>1)$ but at intermediate or moderate pressure, most of the the real gases shows negative deviation from ideal behavior $(Z<1)$.