Electrolysis and Extraction of Aluminium Quiz

What is the process of passing an electric current through ionic substances that are molten or in solution to break them down into elements called?

• Electrolysis

• Distillation

• Filtration

• Fermentation

During electrolysis, which type of ions move to the negative electrode (cathode)?

• Positively charged ions

• Negatively charged ions

• Neutral atoms

• Electrons only

Which statement best explains why cryolite is used in the extraction of aluminium by electrolysis?

• It increases the melting point of aluminium oxide.

• It acts as a catalyst for the reaction.

• It lowers the melting point of aluminium oxide, reducing energy costs.

• It reacts with aluminium to form an alloy.

Explain why the positive electrode (anode) in the extraction of aluminium must be continually replaced.

• It dissolves in the electrolyte.

• It reacts with oxygen to produce carbon dioxide.

• It melts during the process.

• It is consumed by aluminium ions.

During the electrolysis of aluminium oxide, what forms at the negative electrode (cathode)?

• Oxygen gas

• Aluminium metal

• Carbon dioxide

• Chlorine gas

Which ions are present in an aqueous solution in addition to the ions from the salt?

• Only H+ ions

• Only OH- ions

• Both H+ and OH- ions

• Only metal ions

At the negative electrode (cathode), which element is discharged?

• The most reactive element

• The least reactive element

• The element with the highest atomic number

• The element with the lowest atomic number

In aqueous solutions of reactive metal salts, what is evolved at the cathode instead of the metal?

• Oxygen gas

• Chlorine gas

• Hydrogen gas

• Nitrogen gas

Why does the blue colour of the electrolyte fade during the electrolysis of aqueous copper sulfate?

• The temperature increases

• Copper ions are removed from the solution and reduced to copper atoms

• Water evaporates

• Oxygen is produced at the cathode

During the electrolysis of aqueous copper sulfate, what forms at the anode?

• Copper metal

• Hydrogen gas

• Oxygen gas

• Silver metal