In which case will the equilibrium constant (K) be less than 1 at 298 K?

Question

(a) DeltaH = 4.55 kJ/mol ,deltaS = 28.0 J/mol K

(b) delta H = - 4.55 kJ/mol ,deltaS = 28.0 J/mol K

(c)deltaH = 4.55 kJ/mol ,deltaS= - 28.0 J/mol K

(d) both (a) and (b)
I know the answer is c but I don't know how to approach it.

Answer 1

dG = dH - TdS
Substitute and solve for dG.

Then dG = -RTlnK
Substitute and solve for K.