Consider the van der Waals constants, a and b, for the following gases: Gas Ar Ne Kr Xe a/(atm dm⁶mol⁻²) 1.3 0.2 5.1 4.1 b/(10⁻²dm³mol⁻¹) 3.2 1.7 1.0 5.0 Which gas is expected to have the highest critical temperature?
Ar
Ne
Kr
Xe
Solution:
Correct option is A. Kr Tc = 8a/27Rb Greater value of a/b, higher is Tc Gas a/b Ar = 1.3/3.2 = 0.406 Ne = 0.2/1.7 = 0.118 Kr = 5.1/1 = 5.1 Xe = 4.1/5 = 0.82 ∴ Tc has order: Kr > Xe > Ar > Ne