Question

1.Calculate time required to deposit 0.100 g of Thallium on a cathode when 100mA current is passed through a 100Ml 0.01M Thallium solution.

2. A solution containing an unknown concentration of Cu2+ ions gives a diffusion current of 12.3 µA on a DC polarogram. Upon addition of 0.100 mL of 1.00 x 10-3 M Cu2+ solution to the 5ML of the Unknown, the new current is 28.2µA. Calculate the concentration of CU2+ in the unknown solution

3. Zinc is to be used as an internal standard for the polarographic analysis of thallium. A standard solution containing twice the concentration of zinc as Thallium has a diffusion current of 1.89 µA for Ti and 3.50 µA for Zn. A 10.0g alloy was dissolved in 500 mL, 25 mL of this solution was mixed with 25 mL of 1.0 x 10-3 M Zn 2+ solution. The diffusion currents of this final solution are 18.2µA for Tl+ and 14.5µA for Zn+. Calculate % Ti in the sample analysed

Answer 1