4.3.2 Electrolysis of molten ionic compounds

• One application of electrolysis is extracting metals from ores
• What are molten ionic compounds?

  Ionic compounds in liquid state
• Match the property with the state of the ionic compound:

  Solid ↔️ Ions are fixed

  Molten ↔️ Ions move freely
• At the anode, anions are oxidized to form elemental gas.

  True
• What are the ions involved in the electrolysis of molten sodium chloride (NaCl)?

  Na+ and Cl-
• What is the main difference between electrolysis and a normal chemical reaction?

  Requires electrical current
• What is the electrical conductivity of molten ionic compounds?

  Conducts electricity
• What are the ions involved in the electrolysis of molten sodium chloride?

  Na+ and Cl-
• Electrolysis requires an external electrical current to occur.


  True
• In the solid state, ions in ionic compounds are locked in a crystal lattice
• Steps of electrolysis in molten ionic compounds

  1️⃣ Electrodes are placed in the molten compound

  2️⃣ Electric current is applied

  3️⃣ Positively charged cations move to the cathode

  4️⃣ Negatively charged anions move to the anode

  5️⃣ Cations are reduced at the cathode

  6️⃣ Anions are oxidized at the anode
• Cations are positively charged ions that move towards the negatively charged cathode
• In the electrolysis of molten NaCl, chloride ions (Cl-) move towards the positively charged anode
• Molten ionic compounds are ionic compounds that have been heated to a temperature where they are in a liquid state.
• Steps involved in the electrolysis of molten ionic compounds:

  1️⃣ Electrodes are placed in the molten ionic compound

  2️⃣ An electric current is applied

  3️⃣ Positively charged cations move to the cathode

  4️⃣ Negatively charged anions move to the anode

  5️⃣ Cations are reduced at the cathode

  6️⃣ Anions are oxidized at the anode
• In the electrolysis of molten sodium chloride, chlorine gas forms at the anode.
• What is the definition of electrolysis?

  Using electric current for non-spontaneous reactions
• Match the application of electrolysis with its example:

  Extracting metals ↔️ Aluminium from bauxite

  Electroplating ↔️ Chrome plating

  Hydrogen production ↔️ Electrolysis of water
• Molten ionic compounds conduct electricity because ions can move freely.


  True
• What happens to cations at the cathode during electrolysis?

  They are reduced
• Match the ion with its charge:

  Cations ↔️ Positive

  Anions ↔️ Negative
• Electrolysis is the process of using an electric current to drive a non-spontaneous chemical reaction
• In their solid state, ions in ionic compounds are locked in a crystal lattice, preventing electrical conductivity.


  True
• At the cathode, cations are reduced
• What is the key difference between molten and aqueous electrolysis in terms of ion mobility?

  Ions move freely in molten compounds