Question

In an electroplating experiment, $m$ g of silver is deposited when 4 A of current flows for 2 minutes. The amount in g of silver deposited by 6 A of current for 40 seconds will be

• A. $4m$
• B. $2m$
• C. $\frac{m}{2}$
• D. $\frac{m}{4}$

Answer 1

The correct option is C $\frac{m}{2}$

According to Faraday's law of electrolysis, the mass deposited is:

$m=zIt$,
where $z=$ electrochemical equivalent of substance.
Here, in both cases, substance is silver.

So $z$ will be constant.
Now, $m_1=z\times 4\times (2\times 60)=480z$
and $m_2=z\times 6\times 40=240z$
Thus, $\frac{m_2}{m_1}=\frac{240z}{480z}=\frac{1}{2}$

or, $m_2=\frac{m_1}{2}=\frac{m}{2}$