Question

During refining of metals using electrolysis:

• A. Electrode at anode gets thinner and electrode at cathode gets thicker in size
• B. Electrode at anode gets thicker and electrode at cathode gets thinner in size
• C. No change of size is observed during refining of metals
• D. High active metals (impurites) which fall of the electrode are present in anode mud.

Answer 1

The correct option is A Electrode at anode gets thinner and electrode at cathode gets thicker in size

Example of purification of metals using electrolysis:
Purification of impure copper:
Obtained by dipping two $Cu$ strips in a solution of $Cusalt\left(CuSO4\right)$
Anode:
$\text{The impure}Cu(\text{containing}Zn,Fe,Ag,andAu\text{as impurities})$
Impurities $FeandZn$ are more easily oxidized than $Cu$ and dissolve at the anode.The less active metals
simply fall off the electrode and settle to the bottom of the container known as anode mud

Cathode :
$\text{Thin strip of pure}Cu$
$C{u}^{2+}$ ions are reduced in preference to $Z{n}^{2+}/F{e}^{2+}$ ions which remain in the solution. This is because $E_{reduction}^0$ value of $Cu$ is higher than that of $FeandZn$
Gradually, the impure copper anode dissolves ,and the pure copper cathode, grows larger