Equilibria in ethylenediamine. I. The relative dissociation constants of silver salts and alkali metal halides

The relative dissociation constants of a series of silver salts and alkali metal halides has been determined potentiometrically in ethylenediamine using cells of the type Reference electrode//AgX(C₁)/Ag and Reference electrode//AgX(C₁). MX(C₂)/Ag. Silver chloride was found to exhibit typical weak electrolyte behavior and the absolute value of its dissociation constant is estimated to be less than 10^-5. The values of pK_AgCl - pK_MX for the specified MX are: LiCl, -0.33; NaCl, -0.18; KCl, -0.01; RbCl, +0.03; CsCl, +0.22; AgBr, -0.63; LiBr, -0.67; NaBr, -0.50; KBr, -0.72; RbBr, -0.69; CsBr, -060: AgI -1.35; LiI, -0.46; NaI, -0.24, KI, -0.23; RbI, -0.42; CsI, -0.36; (n-C₄H₉)₄NI, -0.44; AgOAc, +0.88; AgSCN, +1.03 and AgNO₃, 1.34. Silver iodide reacts with both sodium potassium, rubidium and cesium iodides according to the reaction AgI + MI ⇄ AgI·MI. The equilibium constants for the reaction as written are 1.33, 1.13, 1.60 and 1.58 for sodium, potassium, rubidium and cesium iodides, respectively. Silver cyanide is monomeric in ethylenediamine and dissociates into silver and argentocyanide (Ag(CN)₂^-) ions.