aqueous solutions

• What should you be able to describe by the end of the video?

  The reactions during electrolysis of aqueous solutions
• What does the term "aqueous" mean?

  Dissolved in water
• What ions are formed when water molecules ionize?

  Hydrogen ions and hydroxide ions
• Which ions are present in copper sulfate solution?

  Copper ions and sulfate ions
• What happens at the cathode during electrolysis of copper sulfate solution?

  ions are reduced to form atoms
• What determines which ion is reduced at the cathode?

  The reactivity series of the ions
• What is the rule regarding hydrogen production at the cathode?

  Hydrogen is produced if the metal is more reactive
• What is the characteristic of electrodes used in electrolysis?

  They are inert and do not react
• What metal is often used as an inert electrode?

  Platinum
• What type of reaction occurs at the cathode?

  Reduction reaction
• What type of reaction occurs at the anode?

  Oxidation reaction
• What are the key points to remember about electrolysis of aqueous solutions?

  • Electrolysis involves ions in solution
  • Positive ions move to the cathode
  • Negative ions move to the anode
  • Products depend on reactivity series
  • Electrodes are inert and do not react
• What are the differences between electrolysis of molten compounds and aqueous solutions?

  • Molten: Only two ions involved
  • Aqueous: Water ionizes, adding hydrogen and hydroxide
  • Products depend on reactivity of ions
• What does the term 'aqueous' mean?

  Dissolved in water
• What ions are produced when water molecules split?

  Hydrogen ion H+ and hydroxide ion OH-
• What are the two ions present in sodium chloride solution?

  Sodium ion Na+ and chloride ion Cl-
• Which electrode is the cathode?

  The negative electrode
• What determines which ion will react at the cathode?

  The reactivity series
• What is produced at the cathode when sodium is more reactive than hydrogen?

  Hydrogen gas
• What is produced at the anode if the solution contains halide ions?

  The halogen will be produced
• What gas is produced at the anode in sodium chloride solution?

  Chlorine gas
• What happens to the hydrogen ion at the cathode?

  It gains an electron to form hydrogen atom
• What occurs immediately after hydrogen atoms form at the cathode?

  They pair to form hydrogen molecule H2
• How do we represent the formation of hydrogen gas in half equations?

  By doubling the equation
• What does the chloride ion do at the anode?

  It loses an electron to form chlorine atom
• Why do chlorine atoms pair at the anode?

  To form a chlorine molecule
• What are the key outcomes of the electrolysis of aqueous solutions?

  • Describe reactions during electrolysis
  • Predict products at electrodes
  • Write half equations for reactions