Question

What will be the current efficiency during electrodeposition of copper metal in which $9g$ of copper is deposited by passage of $3A$ current for $10,000s$?

• A. 66%
• B. 91%
• C. 100%
• D. 74%

Answer 1

The correct option is B 91%

Deposition of copper metal
Reaction will be,
$C{u}^{2+}\left(aq\right)+2e^{-}\to Cu\left(s\right)$
$n-factor=2$
$\text{Atomic mass of Cu}=63.5g$
$\text{Time, t}=10000s$
$\text{Current, I}=3A$
$\text{Mass deposited experimentally,}{W}_1=9g$

$\text{Theoretical Mass, W}=\frac{\text{Atomic Mass}}{n\times F}\times I\times t$

$W=\frac{63.5}{2\times 96500}\times 3\times 10000$

$W=9.87g$

Current efficency is the ratio of the actual mass deposited to the theoretical mass produced by Faraday's law

$\text{Current Efficency}=\frac{\text{Actual Mass}}{\text{Theoretical Mass}}\times 100\%$

$\text{Current Efficency}=\frac{9}{9.87}\times 100\%$

$\text{Current Efficency}=91.18\%$

$\text{Current Efficency}\approx 91\%$