The correct answer is Option (3) → Only (C)
(A) It provides surface either for oxidation or for reduction reaction.
- In an electrochemical cell, the reaction (oxidation at the anode, reduction at the cathode) must occur on the electrode surface.
- An inert electrode serves as the site where the electron transfer occurs, even though the electrode material itself doesn't chemically change. For example, in the reduction of $Fe^{3+}$ to $Fe^{2+}$ at the cathode, the platinum electrode provides the surface for the $Fe^{3+}$ ions to accept electrons.
- Statement (A) is suitable.
(B) It does not participate in the cell reaction.
- An inert electrode's primary characteristic is that it is chemically unreactive with the electrolyte solution and the products/reactants. It acts as a passive conductor.
- Statement (B) is suitable.
(C) It provides surface for redox reaction.
- A redox reaction is a reaction where both oxidation and reduction occur. While an entire cell involves a redox reaction (oxidation at the anode, reduction at the cathode), a single electrode (anode or cathode) is the site for only one half-reaction (either oxidation or reduction, but not both simultaneously).
- The entire cell setup, which includes both the inert anode and inert cathode, facilitates the overall redox reaction. However, a single electrode (like the cathode) only provides the surface for the reduction half-reaction. Stating that a single inert electrode provides the surface for the entire redox reaction is technically inaccurate, as the redox process requires two distinct half-cell surfaces.
- Statement (C) is the least suitable.
(D) It provides surface for conduction of electrons.
- Inert electrodes are highly conductive metals (like Pt). Their role is to transport electrons into or out of the external circuit to the reacting species in the solution. This is essential for the flow of electric current.
- Statement (D) is suitable.
Conclusion
Statements (A), (B), and (D) accurately describe the function of an inert electrode. Statement (C) is inaccurate because a single electrode is the site for one half-reaction (oxidation or reduction), not the complete redox reaction.
The statement that is not suitable is (C). |
