ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Spectrophotometric determination of the activity of strontium and calcium ions by the metal-indicator method

R. Kohn

Institute of Chemistry, Slovak Academy of Sciences, 809 33 Bratislava

Abstract: Tetramethylmurexide metallochromic indicator was used for spectrophotometric detn. of the activity of Sr²⁺ ions. Single-ion activity coeffs. γ_Sr²⁺ as detd. in mixed solns. of SrCl₂ and KCl (ionic strength I ≤ 0.05), are in a very good agreement with those calcd. according to Debye and Hueckel equation (Δγ_Sr²⁺ < +0.005); at a higher ionic strength I = 0.10-0.15, Δγ_Sr²⁺ = +0.02. This method is suitable for detn. of the activity a_Sr²⁺ at (0.1 -2.0) × 10-3. The effect of some simple salts on the detn. of the Sr²⁺ and Ca²⁺ activity has been described. The use of Debye and Hueckel equation and MacInnes' convention for the calcn. of single-ion activity coeffs. γ_Sr²⁺ and γ_Ca²⁺ in dil. solns. of SrCl₂ (I ≤ 0.05) and CaCl₂ (I ≤ 0.15) was confirmed.

Full paper in Portable Document Format: 285a625.pdf

Chemical Papers 28 (5) 625–632 (1974)