When $CuSO_4$ solution is electrolysed using platinum electrodes, which of the following is true?

Copper is liberated at cathode and oxygen at anode

The correct answer is Option (4) → Copper is liberated at cathode and oxygen at anode

When \(CuSO_4\) (copper(II) sulfate) solution is electrolyzed using platinum electrodes, the electrolysis involves both oxidation and reduction reactions occurring at different electrodes. Here is a detailed breakdown of the process:

Electrolysis is a process where electrical energy is used to drive a non-spontaneous chemical reaction. In an electrolytic cell, two electrodes—cathode (negative) and anode (positive)—are immersed in an electrolyte solution. The electrolyte contains ions that participate in the redox (reduction-oxidation) reactions.

Composition of the Electrolyte

In \(CuSO_4\) solution, the main ions present are:

\(Cu^{2+}\) ions (copper ions)

\(SO_4^{2-}\) ions (sulfate ions)

Water molecules (\(H_2O\)) which can also dissociate into \(H^+\) and \(OH^-\) ions.

Reactions at the Electrodes

At the Cathode (Reduction Reaction)

Reduction of Copper Ions:

At the cathode, where reduction occurs, \(Cu^{2+}\) ions gain electrons to form solid copper.

The half-reaction can be written as:

\(Cu^{2+} + 2e^- \rightarrow Cu(s)\)

This reaction results in the deposition of copper metal on the cathode.

At the Anode (Oxidation Reaction)

Oxidation of Water:

At the anode, where oxidation occurs, water molecules are oxidized to produce oxygen gas and protons (\(H^+\)).

The half-reaction can be written as:

\(2H_2O \rightarrow O_2(g) + 4H^+ + 4e^-\)

This results in the release of oxygen gas at the anode.

Summary of Products

At the Cathode: Copper metal is deposited.

At the Anode: Oxygen gas is evolved.

Conclusion

In summary, during the electrolysis of \(CuSO_4\) solution using platinum electrodes:

Copper is liberated at the cathode, where \(Cu^{2+}\) ions are reduced to solid copper.

Oxygen is liberated at the anode, where water is oxidized.

Thus, the correct statement is: Copper is liberated at the cathode and oxygen at the anode.

This process is important in electrochemistry and has practical applications in electroplating and the purification of metals