Question 1

Select the correct definition for electrolysis.

Accepted Answer

Breaking down a substance using electricity

Answer

Melting a substance using electricity

Answer

Reacting two substances to generate electricity

Answer

Forming a substance using electricity

Question 2

Which word describes the positive electrode?

Accepted Answer

anode

Answer

cathode

Answer

electrolyte

Answer

aqueous

Question 3

Select the type of bond that is found in substances that can be electrolysed.

Accepted Answer

ionic

Answer

metallic

Answer

covalent

Answer

alloy

Question 4

Which equation represents the overall reaction in the electrolysis of molten Aluminium oxide (or Aluminium ore)?

Accepted Answer

aluminium oxide → aluminium + oxygen

Answer

aluminium + oxygen → aluminium oxide

Answer

aluminium + oxygen + hydrogen → aluminium oxide + water

Answer

aluminium oxide + water → aluminium + oxygen + hydrogen

Question 5

Which sentence about what happens during electrolysis is correct?

Accepted Answer

Substances are broken down into ions and move to oppositely charged electrodes.

Answer

Substances are broken down into elements and move to oppositely charged electrodes.

Answer

Substances are broken down into ions and move to neutral electrodes.

Answer

Substances are broken down into atoms and move to negatively charged electrodes.

Question 6

What moves through the electrolyte to the electrodes when a substance is electrolysed?

Accepted Answer

ions

Answer

atoms

Answer

protons

Answer

electrons

Question 7

Which statement about electrolysis is true?

Accepted Answer

During electrolysis, water molecules break down into H+ and OH ions.

Answer

During the electrolysis of aqueous magnesium hydroxide, magnesium is deposited.

Answer

Ionic compounds in solution can never be electrolysed.

Answer

Only metals higher than hydrogen in the reactivity series are deposited from aqueous solutions.

Question 8

Molten sodium chloride can be electrolysed to form sodium and chlorine.
Which is the correct equation for this electrolysis?

Accepted Answer

2NaCl(l) → 2Na(l)+ Cl2(g)

Answer

Na(l) + Cl2(g) → NaCl(l)

Answer

2Na(l) + Cl2(g)→ 2NaCl(l)

Answer

NaCl(l) → Na(l) + Cl2(g)

Question 9

Which of these ions would be discharged at the cathode first?

Accepted Answer

hydrogen ions

Answer

hydroxide ions

Answer

chloride ions

Answer

sodium ions

Question 10

Which statement about the extraction of aluminium is correct?

Accepted Answer

Oxygen reacts with the anode to form carbon dioxide.

Answer

Bauxite is added to reduce the melting temperature.

Answer

Aluminium forms at the anode.

Answer

Aluminium must be extracted using electrolysis as it is less reactive than carbon.

Question 11

Which statement about what happens at the electrodes during electrolysis is correct?

Accepted Answer

Ions form neutral elements at the positive electrode.

Answer

Ions are reduced at the positive electrode.

Answer

Ions are oxidised at the negative electrode.

Answer

Ions lose electrons at the negative electrode.

Question 12

Which ion will undergo oxidation during electrolysis?

Accepted Answer

Cl-

Answer

Al3+

Answer

Na

Answer

H+

Question 13

Which pair of half equations correctly represents the electrolysis of molten
aluminium oxide, Al2O3?

Accepted Answer

At the cathode: Al3+(l) + 3e → Al(l)
At the anode: 2O2(l) → O2(g) + 4e-

Answer

At the cathode: Al3+(l) + 3e → Al(s)
At the anode: 2O2(l) → O2(l) + 4e-

Answer

At the cathode: 2O2(l) → O2(g) + e
At the anode: Al3+(l) + 3e → Al(l)

Answer

At the cathode: Al2+(l) + 2e → Al(l)
At the anode: 2O2(l) → O2(g) + 4e-

Question 14

Which reaction occurs at the anode during the electrolysis of brine, NaCl(aq)?

Accepted Answer

2Cl(aq) → Cl2(g) + 2e-

Answer

Na+(aq) + e → Na(l)

Answer

4OH(aq) → 2H2O(l) + O2(g) + 4e-

Answer

2H+(aq) + 2e → H2(g)

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