Electrolysis

• What is the only source of ions in molten ionic compounds?


  One source of ions
• Why can't an ionic solid be electrolyzed?

  Because ions are in a fixed position
• Why can molten ionic compounds be electrolyzed?

  Because ions can move freely
• What happens to positive metal ions at the cathode during electrolysis?

  They are reduced to atoms
• What happens to negative ions at the anode during electrolysis?

  They are oxidized to atoms
• How can you predict the products of electrolysis of molten substances?

  By guessing a half equation's right
• What complicates the electrolysis of aqueous solutions compared to molten substances?

  Presence of hydrogen and hydroxide ions
• What is produced at the cathode if H plus ions are present and the metal reacts with hydrogen?


  Hydrogen gas
• What is produced at the cathode if the metal is less reactive with hydrogen?


  A solid layer of real metal
• What is produced at the anode if halides are present during electrolysis?

  Molecules of chlorine, boron, and fluoride
• What happens at the anode if no halides are present?

  Oxygen is transformed to form hydroxide ions
• What gases are produced during electrolysis of aqueous solutions?

  Chlorine and hydrogen gas