Electrolysis of solutions

• What is the process of electrolysis used for?

  To break down electrolytes to form elements using electricity
• What can be predicted from a given electrolyte during electrolysis?

  The products of electrolysis
• What is the definition of an electrical conductor?

  • A material that allows an electrical current to pass through easily
  • It has low resistance
• What ions are formed when water dissociates?

  Hydrogen ions (H⁺) and hydroxide ions (OH^-)
• What happens to H⁺ ions during the electrolysis of acidified water?

  They are attracted to the cathode and gain electrons to form hydrogen gas
• What do OH^- ions do at the anode during electrolysis?

  They lose electrons and form oxygen gas
• What is the overall balanced equation for the electrolysis of water?

  2H₂O(l) → 2H₂(g) + O₂(g)
• How does the volume of hydrogen produced compare to the volume of oxygen during electrolysis?

  The volume of hydrogen is twice the volume of oxygen
• What occurs during the electrolysis of dissolved ionic compounds?

  • Ions compete at each electrode to gain or lose electrons
  • The product at the cathode depends on the reactivity of the metal compared to hydrogen
• What determines whether hydrogen or a metal is produced at the cathode?

  It depends on the position of the metal in the reactivity series
• What product is formed at the cathode during the electrolysis of sodium chloride solution?

  Hydrogen will be produced because sodium is more reactive than hydrogen
• What product is formed at the cathode during the electrolysis of copper chloride solution?

  Copper will be produced because copper is less reactive than hydrogen
• What is produced at the anode during the electrolysis of water?

  Oxygen is produced from hydroxide ions
• What happens at the anode if halide ions are present during electrolysis?

  Negatively charged halide ions lose electrons and form the corresponding halogen
• What are the products formed at the anode during the electrolysis of different electrolytes?

  • Chloride (Cl^-): Chlorine (Cl₂)
  • Bromide (Br^-): Bromine (Br₂)
  • Iodide (I^-): Iodine (I₂)
  • Sulfate (SO₄^2-): Oxygen (O₂)
  • Nitrate (NO₃^-): Oxygen (O₂)
• What product is formed at the positive electrode during the electrolysis of concentrated sodium sulfate solution?

  Oxygen will be produced