OCR Gateway GCSE Chemistry

Topic Questions

3.4 Electrolysis

11 mark

During the electrolysis of molten lead bromide, bromine is made at the anode.

Which half equation shows that bromine is made at the anode?

  • 2Br- → Br2 + 2e-

  • Br- → Br + e-

  • Br2 + 2e- → 2Br- 

  • 2Br- → Br2 - 2e-

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11 mark

Sodium chloride solution can undergo electrolysis. 

What product will be formed at the negative electrode?

  • Oxygen

  • Chlorine

  • Hydrogen

  • Sodium

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21 mark

Electrolysis can be used to separate molten lead bromide. 

Which statement is true for what happens at the negative electrode?

  • Lead atoms are oxidised 

  • Lead atoms are reduced 

  • Lead ions are oxidised 

  • Lead ions are reduced 

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31 mark

When copper(II) sulfate undergoes electrolysis, it produces oxygen gas at the positive electrode.

The unbalanced half equation below represents the reaction that occurs at the positive electrode.

Which numbers will correctly balance the half equation?

___ OH-    →    O2   +   ___ H2O  +  ___ e-

  • 2,2,2

  • 2,4,2

  • 4,2,4 

  • 4,4,2 

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41 mark

During the the electrolysis of copper sulfate solution, copper ions move to the negative electrode.

What is the reason for this?

  • Copper is less reactive than hydrogen and consists of negatively charged ions

  • Copper is more reactive than hydrogen and consists of negatively charged ions

  • Copper is less reactive than hydrogen and consists of positively charged ions

  • Copper is more reactive than hydrogen and consists of positively charged ions

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51 mark

A student was investigating the electrolysis of zinc chloride. 

3-4-q5-ocr-gcse-mcq-chemistry

What is the correct reason for electrolysis not working? 

  • Solid zinc chloride has been used 

  • The electrodes don't conduct electricity 

  • The power supply is not connected properly 

  • The crucible is too small to allow ions to flow 

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61 mark

Some metals, such as aluminium, are extracted from their ores using electrolysis. 

Why are some metals extracted using electrolysis? 

  • They are native metals 

  • They are more reactive than carbon 

  • They have low melting points 

  • They conduct electricity  

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71 mark

During the electrolysis of molten potassium chloride, what is made at the cathode?

  • Chlorine

  • Hydrogen

  • Potassium

  • Potassium hydroxide

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81 mark

An aqueous solution of concentrated sodium chloride is electrolysed. Bubbles are seen at the positive electrode.

What is the name of the substance produced at the positive electrode?

  • Chlorine

  • Hydrogen

  • Sodium

  • Oxygen

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91 mark

During the electrolysis of molten copper chloride, what is made at the positive electrode (anode)?

  • Chloride

  • Chlorine

  • Copper

  • Hydrogen

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