Which statement best distinguishes electrolysis from spontaneous redox in a galvanic cell?

• A. Electrolysis requires energy input to drive non-spontaneous reactions.
• B. Electrolysis generates electricity spontaneously.
• C. Electrolysis occurs only in molten salts.
• D. Electrolysis does not involve oxidation-reduction reactions.

Answer: (A)

The key idea is that electrolysis is driven by external energy to force a non-spontaneous redox reaction. In electrolysis, an external power source pushes electrons through the circuit, driving oxidation at one electrode and reduction at the other even though the overall process would not occur on its own. This contrasts with a galvanic cell, which relies on spontaneous redox chemistry to generate electricity without outside input. Because of this, the statement that best distinguishes electrolysis from spontaneous redox in a galvanic cell is that electrolysis requires energy input to drive non-spontaneous reactions. The other points aren’t accurate: electrolysis does involve redox at the electrodes, so claiming no redox is incorrect; it isn’t limited to molten salts—it can occur in molten salts or in aqueous solutions; and it does not generate electricity spontaneously, it consumes electrical power.