4.3.2.1 Products at each electrode during electrolysis

• What is electrolysis?

  A process using electricity to break down substances
• How does electrolysis relate to chemical compounds?

  It decomposes them into their elemental parts
• What charge do anions have?

  Negative (-)
• What are molten salts?

  Ionic compounds heated to become liquids
• In what process are molten salts commonly used?

  Electrolysis
• What does electrolysis do to a substance?

  It breaks it down into its constituent elements
• How is an anion formed in sodium chloride?

  Chlorine gains an electron to form $Cl^{ - }$
• What happens to ions when molten salts melt?

  They become free to move
• What is the name of the part of the electrolytic cell where reduction occurs?

  Cathode
• What happens during electrolysis to ionic compounds?

  • Electricity breaks down ionic compounds
  • Produces constituent elements
  • Involves oxidation and reduction reactions
• What process occurs at the cathode?

  Reduction (gains electrons)
• What is the name of the part of the electrolytic cell where oxidation occurs?

  Anode
• What is the charge of the cathode in an electrolytic cell?

  Negative
• What are the characteristics of cations and anions in molten salts?

  • Cations:
  • Positively charged ions
  • Example: $Na^{ + }$
  • Anions:
  • Negatively charged ions
  • Example: $Cl^{ - }$
• What are the roles of the cathode and anode in an electrolytic cell?

  • Cathode:
  • Charge: Negative
  • Process: Reduction (gains electrons)
  • Attracts: Cations
  • Anode:
  • Charge: Positive
  • Process: Oxidation (loses electrons)
  • Attracts: Anions
• What happens to molten salts in an electrolytic cell?

  They contain freely moving ions
• What happens to $Na^{ + }$ at the cathode during electrolysis?


  $Na^{ + }$ becomes $Na$
• What happens to $Cl^{ - }$ at the anode during electrolysis?


  $Cl^{ - }$ becomes $Cl_{2}$
• What are half reactions in electrolysis?

  Chemical reactions at each electrode
• What type of ions does the anode attract?

  Anions
• What role does the power source play in an electrolytic cell?

  It supplies electrical energy for ion movement
• What are the main components of an electrolytic cell?

  • Cathode (reduction)
  • Anode (oxidation)
  • Power source (battery)
  • Electrolyte solution
• What do half reactions involve during electrolysis?

  Exchange of electrons
• What is the half reaction at the anode?

  $2Cl^{ - }(l) \rightarrow Cl_{2}(g) +$$2e^{ - }$
• What is reduction in terms of electron transfer?

  Gaining electrons
• What type of ions does the cathode attract?

  Positive ions (cations)
• What ions are involved in the anode half reaction?

  $Cl^{ - }$
• What is a cation?

  A positively charged ion
• What are the two types of ions?

  Cations and anions
• What are molten salts?

  Ionic compounds that have melted
• Why are molten salts excellent conductors of electricity?

  Because ions are free to move
• How does the power source affect the movement of ions in an electrolytic cell?

  It drives the movement to respective electrodes
• Why can molten salts conduct electricity?

  Their ions can move freely in liquid state
• How does the process at the cathode differ from that at the anode during electrolysis?

  Cathode: reduction; Anode: oxidation
• Why can ions in molten salts move freely?

  Because they have been heated until melted
• What ions are involved in the cathode half reaction?

  $Na^{ + }$
• How are ionic compounds formed?

  By electrostatic attraction between ions
• What do sodium ions become after gaining electrons at the cathode?

  Sodium metal ($Na$)
• What is the role of anions at the anode?

  Anions lose electrons and form gases or solids
• What is the role of cations at the cathode?

  Cations gain electrons and form new substances