Table 1. Distribution Ratios for Extraction of Zn(II) by 0.2 mol L^–1 TOMAC in Toluene from 30.6 mmol L^–1 ZnCl₂ in HCl or a Different Monovalent Salt and the Salt Cation Standard State Gibbs Free Energy of Hydration (ΔG_hyd,exp⁰)³².

cation	DZn(II) at 4 mol L–1 chloride	ΔGhyd,exp0 (kJ mol–1)
H+	(3.6 ± 0.2) · 102	–1050
Li+	(1.9 ± 0.1) · 103	–475
Na+	(1.3 ± 0.1) · 103	–365
K+	(5.8 ± 0.3)· 102	–295
NH4+	(5.4 ± 0.3)· 102	–285
Rb+	(3.4 ± 0.2) · 102	–275
Cs+	(7.5 ± 0.4) · 101	–250