Cd amalgam is preapred by electrolysis of a solution `CdCI_(2)` using a mercury cathode. How long should a current of `5A` be passed in order to prepare `12% Cd-Hg` amalgam on a cathode of `2g, Hg`( atomic weight of `Cd = 112.4)`

Answer

`t = 93.65 sec`

Explanation

`2mg` of Hg contains `= (12)/(88) xx 2` gm of Cd
`= 0.27gm` of Cd
`Cd^(+2) +2e^(-) rarr Cd`
`n_(Cd^(+2)) = (0.27)/(112.4) n_(E) = (2 xx 0.27)/(112.4)`
`I = (q)/(t)`
`t = (2 xx 0.27)/(112.4) xx (96500)/(5)`
`t = 93.653`