Exams › JEE Advanced › Chemistry
From the list Na, Hg, S, Pt and graphite, which substances are suitable for use as electrodes in the electrolysis of aqueous solutions?
- Hg and Pt
- Hg, Pt and graphite
- Na, S
- Na, Hg, S
Correct answer: Hg, Pt and graphite
Solution
Na reacts violently with water, so it cannot serve as an electrode in aqueous solution. Sulphur is a non-metal and a poor electrical conductor, so it is unsuitable. Mercury (a liquid metal, used as a cathode in the chlor-alkali Hg-cell), platinum (an inert noble metal), and graphite (a conducting, inert non-metal) all conduct and are chemically stable enough to act as electrodes in aqueous electrolysis.
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