Dielectric shielding of ionic charges in aqueous solutions of different ionic strength

In aq. solns. contg. 1,3-diaminopropane (tn) with ionic strength μ = 0.05-3.01M (KCl) at 20°, the Gibbs free energy change (-ΔG in kcal/mole) and the enthalpy change (-ΔH, in kcal/mole) for H2tn2+ + tn → 2 Htn+ (1), the effective dielec. const. (ε). and (-δε/δT), resp., are: 2.41, 0.55, 31, 0.070 for μ = 0.11; 2.25, 0.88, 35, 0.046 for μ = 1.01; 2.21, 1.05, 36, 0.031 for μ = 2.01; 2.23, 1.26, 36, 0.015 for μ = 3.01. The variation of ΔH as a function of μ was represented by ΔH = -Ael[1 + (T/ε)(δε/δT)] where Ael is the electrostatic energy gained in reaction (1).