Question

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

• A.
• B.
  
• C.
• D.

Answer 1

The correct option is C

P(V-b) =RT
$\Rightarrow PV-Pb=RT$
$\Rightarrow \frac{PV}{RT}=\frac{Pb}{RT}+1$
$\Rightarrow Z=1+\frac{Pb}{RT}$
Hence Z > 1 at all pressures.
This means, repulsive tendencies will be dominant when interatomic distance are small.
Also, interatomic potential is never negative but becomes positive at small interatomic distances and the attractive potential has the negative sign ,while the repulsive potential has the positive sign.