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 gas is given by

Options

A.
B.
C.
D.

Answer

C

Explanation

The given equation is : `P (V - b) = RT`. On comparing it with van der Waals' equation, i.e., `[P + (a)/(V^(2))] [V - b] = RT`, we get :
`a = 0`
Hence, only repulsive forces are present which are contributive only at very close distance. Thus, potential energy will increases abruptly i.e., graph (c) is correct. Dominance of repulsive forces can be confirmed using compressibility factor.
`P(V - b) = RT`
`PV = Pb + RT`
`(PV)/(RT) = (Pb)/(RT) + 1`
`Z = (Pb)/(RT) + T`, i.e., `Z gt 1` (Repulsive forces)