A real gas follows van der waals equation. Find the compressibility for 1 mol of the gas at its critical temperature.

Explanation

At critical point,
`V=V_(c)=3b,P=P_(c)=(a)/(27b^(2)) and T=T_(c)=(8a)/(27Rb)`
`therefore Z=(PV)/(RT)=((a)/(27b^(2))xx3b)/(Rxx(8a)/(27Rb))=(3)/(8)`