Aqueous Solutions

• What is electrolysis used for?

  To split compounds into their elements
• How does electrolysis work?

  By passing an electric current through an electrolyte
• What must happen for electrolysis to work?

  Ions in the electrolyte must be free to move
• What must be done to insoluble compounds for electrolysis?

  They must be melted into a molten liquid
• How can soluble compounds be prepared for electrolysis?

  By dissolving them in water
• What equipment is needed for an electrolysis experiment?

  • Beaker full of electrolyte
  • Two electrodes (anode and cathode)
  • Wire connecting electrodes
  • Power supply
• What ions are present in aqueous solutions besides the ionic compound ions?

  Hydrogen ions and hydroxide ions from water
• What does the cathode attract during electrolysis?

  Positive ions from the electrolyte
• What is the rule for discharging ions at the cathode?

  The least reactive ion will be discharged
• What happens if copper ions are present at the cathode?

  Copper ions will be discharged instead of hydrogen
• What happens when halide ions are present at the anode?

  Halide ions will be discharged
• What ions are present in an aqueous solution of copper sulfate?

  Copper 2+ ions and sulfate 2- ions
• What is produced at the cathode during the electrolysis of copper sulfate?

  copper is produced
• What is the equation for the reaction of hydroxide ions at the anode?

  4 OH- → 2 H2O + O2 + 4 e-
• What ions are present in an aqueous solution of sodium chloride?

  Sodium ions, chloride ions, hydrogen ions, hydroxide ions
• What ions are discharged at the cathode during the electrolysis of sodium chloride?

  Hydrogen ions are discharged
• What is discharged at the anode during the electrolysis of sodium chloride?

  Chloride ions are discharged
• What are the products of electrolysis of sodium chloride solution?

  • Hydrogen gas at the cathode
  • Chlorine gas at the anode