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. `I, 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= (RT)/(P)+b`, slope `= (R )/(P)` and intercept b
`V= (PV)/(RT)= 1+(Pb)/(RT), Z gt 1` ie, repulsive forces predominate.