Suggest a suitable material for the electrodes.

• A. Graphite, carbon, steel
• B. Plastic
• C. Wood
• D. Glass

Answer: (A)

Electrodes must conduct electricity and stay chemically stable in the electrolyte. Graphite and other carbon forms are good conductors and are relatively inert in many solutions, so they make reliable, non-reactive electrodes. Steel is a metal that conducts electricity as well, and can be used as an electrode in many setups, though it can corrode or contaminate the solution in some conditions. The other materials listed—plastic, wood, and glass—are insulators and do not conduct electricity, so they wouldn’t work as electrodes.