International Chemistry Olympiad · 1989

Problems

Problem 1To determine the solubility product of copper(II) iodate, $\ce{Cu(IO3)2}$ , a saturated aqueous solution of $\ce{Cu(IO3)2}$ at 25 °C is analysed by iodometric titration in acidic solution: an excess of iodide is added and the liberated iodine is titrated with sodium thiosulphate. $30.00\ \mathrm{cm^3}$ of a 0.100 M sodium thiosulphate solution are needed for $20.00\ \mathrm{cm^3}$ of the saturated solution. (1.1) Write the sequence of balanced equations for the reactions described. (1.2) Calculate the initial concentration of $\ce{Cu^{2+}}$ and the solubility product of copper(II) iodate. Activity coefficients can be neglected.Solutions: 1