redox reaction and electrolysis

What kind of substances can form electrolytes?

• Ionic

• covalent

• metallic

Aluminium reacts with iron(III) oxide as shown.

iron(III) oxide + aluminium → iron + aluminium oxide

Which statement about this reaction is correct?

• Aluminium is oxidised

• iron is oxidised

• iron(III) oxide is oxidised

• Alumininum oxide is reduced

Which of the following is a true statement about the electrolysis of sodium chloride solution?

• Hydrogen forms at the positive electrode

• Sodium forms at the negative electrode

• Chlorine forms at the positive electrode

What is formed at each electrode during the electrolysis of dilute sulfuric acid?

• Hydrogen at the positive electrode and oxygen at the negative electrode

• Hydrogen at the negative electrode and oxygen at the positive electrode

• Hydrogen at the negative electrode and sulfur dioxide at the positive electrode

Which of these changes occurs during electrolysis?

• Negative ions lose electrons at the negative electrode and are oxidised

• Negative ions lose electrons at the positive electrode and are oxidised

• Negative ions gain electrons at the negative electrode and are oxidised

Which of these is a description of oxidation?

• The gain of oxygen

• The loss of oxygen

• The gain of hydrogen

Which substance is the reducing agent in this reaction?

Fe₂O₃ + 3CO → 2Fe + 3CO₂

• Fe₂O₃ (Iron(III) oxide)

• CO (Carbon monoxide)

• CO₂ (Carbon dioxide)

Which of these equations shows reduction taking place?

• Mg → Mg²⁺ + 2e

• Cu - 2e → Cu²⁺

• Cu²⁺ + 2e → Cu

Which element removes oxygen from iron(III) oxide in the industrial extraction of iron?

• Copper

• Calcium

• Carbon

• A

• B

• C

• D