Electrolysis reactions producing oxygen at the anode Steps: - Identify common electrolysis processes: 1 likely molten NaCl (Cl2 at anode), 2 aqueous NaCl (O2 or Cl2 at anode), 3 water (O2 at anode), 4 likely CuSO4 with Cu anode (O2 at anode if inert). - Recall anode reactions: oxygen forms from water oxidation (2H2O → O2 + 4H+ + 4e-) in dilute solutions or pure water. - Check each: process 2 (aqueous NaCl, dilute) and 3 (water electrolysis) produce O2 at anode; 1 and 4 do not primarily. - Match to options: only 2 and 3 fit. Why B is correct: - B selects 2 and 3, where anode reaction is water oxidation per Faraday's electrolysis laws, yielding O2 in aqueous or pure water setups. Why the others are wrong: - A includes 1 (molten NaCl produces Cl2, not O2). - C includes 4 (CuSO4 with Cu anode deposits Cu, O2 only if inert anode but not primary). - D excludes 2 (aqueous NaCl can produce O2 in dilute cases). Not enough information on exact processes 1-4, but based on …