A gas obeys `P(V-b)=RT`. Which of the following are correct about this gas?
I. Isochoric curves have slope `=(R )/(V-b)`
II. Isobaric curves have slope `(R )/(P)` and intercept b.
III. For the gas compressibility factor `=1+(Pb)/(RT)`
IV. The attractive forces are overcome by repulsive forces.

Options

A. I
B. II , III
C. III
D. II ,III , IV

Answer

D

Explanation

`P (V-b) = RT implies P = ( R)/((V-b)) T implies ` slope = `( R)/(V-b) , PV - Pb = RT`
`V = ( R T)/(P) + b` , slope = `( R)/(P)` and intercepts b
`V = (PV)/( RT) = 1 + (Pb)/(RT) , Z gt 1` i.e., repulsive forces predominate.