There are hydrogen bond donors (D), and acceptors (A). When the mixture (A + D) is transferred from water, designated as (w) to a nonpolar solvent (np), the free energy change (ΔG) of transfer is 6.12 kcal mol^-1 for the (A + D) mixture. A and D form a hydrogen bond in this nonpolar solvent and ΔG for this process is -2.4 kcal mol^-1 . When the hydrogen bonded molecule A - D is transferred from water to the nonpolar solvent ΔG for this process is 0.62 kcal mol^-1 . The value of ΔG for the formation of hydrogen bond (A + B ↔ A - B) in water is