Given that ΔH = 0 for mixing of two gases. Explain whether the diffusion of these gases into each other in a closed container is a spontaneous process or not?
o The spontaneity of any process mainly depends on the sign of Gibb’s free energy. A negative ∆G means the reaction will be spontaneous included contribution of the other factors like enthalpy(H) and entropy(S).
o In case of diffusion of the gases, the volume will be increased, therefore entropy will increase i.e. ∆S = positive.
Hence in the relation, ∆G= ∆H - T∆S
despite of ∆H being 0 ,
∆G will be negative (as positive value of ∆S will give a more negative T∆S)
• ∆H=0 ; ∆G= -T∆S= negative.