The correct option is D b=70 ml/mol
dPdV=0 represents the critical point of ammonia.
So, T=Tc=132∘ C, V=Vc=70 ml/mol=0.07 L/mol
Tb=aRb,b=Vc3,a=3PcV2c,
From the above, option d is clearly incorrect.
Also, Tb=9PcVcR
Z=PcVcRTc=38
So, Tb=278Tc≈1377 K=1094∘ C