Gibbs free energy differences between axial-substituted and equatorial-substituted chair conformations of cyclohexane were given in table 2.4

a) Calculate the ratio of equatorial to axial tert-butylcyclohexane at 25 degrees C

b) Explain why the conformation equilibria for methyl, ethyl and isopropyl substituent are comparable but the conformational equilibrium for tert-butylcyclohexan lies considerably farther toward the equatorial conformation