An inert electrode used in electrolysis is usually made from which materials?

• A. Platinum or carbon
• B. Copper
• C. Iron
• D. Silver

Answer: (A)

In electrolysis, an inert electrode is a conductor that doesn't take part in the chemical change at the electrode, it just carries current. The material needs to be chemically stable in the electrolyte and under the applied voltage. Platinum and carbon fit this role well because they resist corrosion and do not readily undergo oxidation or reduction themselves, so the reactions occur with the dissolved ions in the solution rather than with the electrode. Copper, iron, and silver, on the other hand, tend to participate in the reactions or dissolve/plate during electrolysis, making them active electrodes rather than inert.