Ion association in aqueous solutions of some bi-bivalent metal salts.

The work of Davies and his co-workers provides ample evidence of ion-association in aqueous solutions of bi-bivalent metal salts. In the work described in this Thesis, this association has been investigated in aqueous solutions of bivalent metal salts of the acids COOH.(CH[2])[n].COOH. The methods available for determining the dissociation constants of these salts are reviewed, and three of them are discussed in detail. Section 1. Stock and Davies showed that for a solution containing a standard concentration of a sulphone-phthalein indicator, equality of indicator colour denotes equality of the function f[2](H[+]). This fact has been utilised in the determination of the dissociation constants of a number of salts. A method is also suggested for the simultaneous determination of the dissociation constants of a dibasic acid. Section 2. The solubility of copper malonate in water, and in aqueous solutions of malonic acid, sodium malonate and copper sulphate is reported. The enhanced solubility is attributed to the formation of the complex ions CuMal[2''] and Cu[2]Mal[++]. Approximate values are given for the dissociation constants of these two ions. Section 3. An attempt has been made to determine the dissociation constants of the copper salts of oxalic, malonic, succinic and glutaric acids by a spectrophotometric method. The method is critically discussed and it is shown that in these solutions ion-association is too extensive for any quantitative treatment of the available data to be possible. An alternative method is suggested