One mole of a monoatomic real gas satisfies the equation `p(V -b) = RT` where `b` is a constant. The relationship of interatomic potential `V(r )` and interatomic distance `r` for the gas is given by

Options

A.
B.
C.
D.

Answer

C

Explanation

`P (V-b) = RT`
`rArr PV = Pb = RT`
`rArr (PV)/(RT) = (Pb)/(RT) +1`
`rArr Z = 1+(Pb)/(RT)`
Hence `Z gt 1` at all pressure.
This means, repulsive tendencies will be dominant when interatomic distance are small.
This means, interatomic potential is never negative but becomes positive at small interatomic distances.
Hence answer is (C )