Question

An unknown cadmium(II) solution in 0.1 mol L-1 H2S04 was analysed polarographically by standard addition calibration. A 25.00-mL sample of the unknown solution produced a diffusion current of 1.86 uA. Following addition of a 5.00-mL aliquot of 2.12 mmol L-1 Cd2+ standard solution in 0.1 mol L1 H2S04 to the unknown solution, a diffusion current of 5.27 uA was produced (a) Why must H2S04 be present in the above analysis? (b) Describe how the polarogram would look like if there was no H2SO4 used in the above set up. Give a reason for your answer. Find the concentration (in mmol L-1) of Cd2+ in the unknown (c)

Answer 1

Solution:

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