The Products of The Electrolysis of Sodium Chloride

Identify data, plan and perform a first-hand investigation to identify the products of the electrolysis of sodium chloride

  • Different products can be formed when conducting electrolysis of sodium chloride
  • Electrolysis of dilute NaCl produces oxygen gas at the anode and hydrogen gas + hydroxide ions at the cathode
  • Electrolysis of concentrated NaCl produces chlorine gas at the anode and hydrogen gas + hydroxide ionsat the cathode
  • Glowing splint test can be done to identify the gas formed at the electrode
    • the gas formed is hydrogen if a ‘popping’ sound is heard
    • the gas formed is oxygen if the splint reignites
  • Litmus paper or indicators, such as phenolphthalein, can be used to identify products in solution form
    • Presence of chloride ions results to bleaching of litmus paper
    • Presence of hydroxide ion makes the solution with phenolphthalein turn purple
  • Safety measures should be done when handling sodium hydroxide by wearing safety goggles and gloves to prevent burns and eye irritation
  • Experiments involving chlorine gas should be done inside a fumehood as Cl2 gas is deemed toxic and can cause respiratory problems