Question

For electrolysis of aqueous $ZnS{O}_4$ solution using $Zn$ electrodes, which of the following is/are true:

• A. $Zn$ get dissolved at positive terminal electrode
• B. $Zn$ get dissolved at negative terminal electrode
• C. $Zn$ get deposited on negative terminal electrode
• D. $Zn$ get deposited on positive terminal electrode

Answer 1

Answer: (A), (C)

$Zn$ get deposited on negative terminal electrode

The process of using an electric current ​to drive a ​non-spontaneous​ chemical reaction is called electrolysis.
The electrolyte used can be in fused (or molten) state or in aqueous state. It should conduct electricity.

Electrolysis of $ZnS{O}_4$ with $Zn$ electrode:
Two zinc strips are dipped in an aqueous solution of $ZnS{O}_4$ ​

When the DC voltage is applied,
At cathode: $Z{n}^{2+}$ ions get discharged as $Zn$ atoms​
Reaction: $Z{n}^{2+}+2e^{-}\to Zn$

At anode: $Zn$ atoms get dissolved as $Z{n}^{2+}$ ions​
Reaction: $Zn\to Z{n}^{2+}+2e^{-}$

Thus, $Zn$ is deposited at cathode.
Cathode is negative in electrolytic cell because it connects to the negative terminal of battery.

Hence, $Zn$ gets deposited at negative terminal electrode and $Zn$ gets dissolved at positive terminal electrode.
This kind of cell is used in purification of impure metals from their ores. This process is called electroplating/electrorefining.