Example Faraday's law 8.3 Discharging metal ions, electroplating Cylinder of the radius r=1.5cm and length L=5cm should be covered by a layer of metallic chromium with the thickness t=30m (micrometers) Calculate a) time needed for the electrolysis using the current 0.44A (current yield 88% ) in the electrolyzer filled with aqueous solution of chromium(III) sulphate Cr2(SO4)3. b) the decrease of amount (in moles) of chromium(III) sulphate Cr2(SO4)3 in the solution during the electrolysis. Data: M(Cr)=52gmol1, density of metallic chromium is 7.1gcm3. Solution: n=Mm=zFQ=zFI=znIFlowerefficiencyreal=m=VV=StS=2rL+2(r2) Results a): Results b): Cr2(SO4)32CrnCrrt(deposited)=2nC2(SO4)3(decomposed)nC2(SO4)3(decomposed)=mol