Question

Cd amalgam is prepared by electrolysis of a solution of $CdC{l}_2$ using a mercury cathode. Find how long (in minutes) should a current of 5 ampere is passed in order to prepare 12% $Cd-Hg$ amalgam on a cathode of 2.56 g mercury? At. wt. of Cd = 112.40.

Answer 1

$88gHg\text{has}12gCd$
$\therefore 2.56gHg\text{require}=\frac{12\times 2.56}{88}gCd=0.349$
$\because C{d}^{2+}+2e\to Cd[\therefore E_{Cd}=\frac{112.40}{2}]$
Now, $w=\frac{E.i.t}{96500}$
$0.349=\frac{112.4\times 5\times t}{2\times 96500}=120\sec$
$=2\text{minutes}$