Spectrophotometric investigation of equilibria between silver(II) and 2,2′-bipyridine

Abstract

A spectrophotometric study has been made of an aqueous solution of silver(II) containing nitric acid and an excess of 2,2′-bipyridine over the wavelength range 350–550 nm. The data are consistent with the existence of only two complexes related by the equilibrium [Ag(bipy)₂]²⁺+ H⁺⇌[Ag(bipy)]²⁺+ Hbipy⁺. At I= 1.00 mol dm^–3 and at 25 °C, K_h for this equilibrium is found to be (3.3 ± 0.5)× 10^–3. From the variation of K_h with temperature the values for the enthalpy and entropy of the above reaction are found to be 11.5 ± 2.6 kJ mol^–1 and –9 ± 10 J K^–1 mol^–1 respectively.