Question

An electroplating unit plates 3.0 g of silver on a brass plate in 3.0 minutes. Find the current used by the unit. The electrochemical equivalent of silver is 1.12 × 10⁻⁶ kg C⁻¹.

Answer 1

Given:
Mass of silver deposited, m = 3 g
Time taken, t = 3 min. = 180 s
E.C.E. of silver, Z = 1.12 × 10⁻⁶ kg C⁻¹

Using the formula, m = Zit, we get:
$3\times {10}^{-3}=1.12\times {10}^{-6}\times i\times 180$
$$\begin{gathered} \Rightarrow i=\frac{3\times {10}^{-3}}{1.12\times {10}^{-6}\times 180} \\ \Rightarrow i=\frac{1}{6.72}\times {10}^2 \\ \Rightarrow i=14.89\approx 15\mathrm{A} \end{gathered}$$