Effect of Concentration of AgNO3 on the Rate of Formation of a Complex Salt, [Co(H3)6](NO3)3 and Estimation of Molar Concentration of the Complex

Abstract

Different molar concentrations of AgNO₃ (0.10 M, 0.15 M, 0.20 M, 0.25 M and 0.30 M) were prepared and 50.00cm³ of 0.20 M of [CO(NH₃)₆]Cl₃ A new complex was formed  and , the time taken as well as the rate at which the complex was formed were determined for each reaction. The insoluble component (AgCl) and soluble component (new complex) formed were separated from the reaction mixture by filtration. The residue (AgCl) was dried between filter papers in fume cupboard while the filtrate, which contained the new complex was first evaporated and finally crystallized by cooling under tap. The weights and molar concentrations of AgCl and new complex formed were determined. Confirmatory tests of the substituted anions (NO^-₃ and Cl^-) were conducted. The work showed that the times taken for the formation of the new complex and AgCl  were 32 sec, 27 sec, 21 sec, 16 sec and 12 sec. for 0.10 M, 0.15 M, 0.20 M, 0.25 M and 0.30 M of AgNO₃ respectively; the corresponding rates (cm³/sec) were 1.56, 1.85, 2.38, 3.22 and 4.20, respectively; the weights of the AgCl and new complex formed were 27.27g and 58.99g, respectively; the molar concentrations of AgCl and new complex obtained were 0.19 mol/dm³ and 0.17 mol/dm³ and; the qualitative analyses of the swapped anions confirmed the presence of NO^-₃ in the new complex and Cl^- in AgCl.

Keywords: Complex salts; substitution reactions; rate of reaction; crystallization; precipitation.