Electrolysis products identify the electrolyte

Steps:

• Examine diagram for gases at electrodes: hydrogen bubbles at cathode, oxygen at anode.
• Note gas volume ratio: 2:1 (hydrogen to oxygen), indicating water decomposition.
• Confirm inert electrodes rule out metal deposition; focus on aqueous solutions.
• Match to electrolyte where water is primarily electrolyzed, not ions.

Why C is correct:

• Dilute sulfuric acid electrolyzes water via 2H₂O → 2H₂ + O₂, as H⁺ ions facilitate H₂ at cathode and OH⁻ oxidation yields O₂ at anode.

Why the others are wrong:

• A: Copper(II) ions deposit as copper metal at cathode, not hydrogen gas.
• B: Concentrated chloride ions produce chlorine gas at anode, not oxygen.
• D: Ethanol is a non-electrolyte, conducts poorly and yields different products like ethene.

Final answer: C