Electrolysis (OCR GCSE Chemistry A (Gateway))

Exam Questions

1 hour23 questions
11 mark

A student was investigating the electrolysis of zinc chloride. 

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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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21 mark

Solid lead(II) bromide is heated until it is molten. The molten lead (II) bromide then undergoes electrolysis. 

Which substances are formed at each electrode?

anode

cathode

A

bromine

lead

B

lead

bromine

C

bromine

hydrogen

D

hydrogen

lead

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    31 mark

    Concentrated aqueous sodium chloride can be electrolysed.

    Which statement is correct?

    • Hydrogen gas is formed at the anode, and chlorine gas is formed at the cathode.

    • Hydrogen gas is formed at the cathode, and chlorine gas is formed at the anode.

    • Sodium metal is formed at the anode, and chlorine gas is formed at the cathode.

    • Sodium metal is formed at the cathode, and chlorine gas is formed at the anode.

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    41 mark

    During electroplating what are the correct anode (positive electrode) and cathode (negative electrode) products when aqueous copper(II) sulfate is electrolysed using copper electrodes? 

     

    anode product

    cathode product

    A

    copper(II) ions

    copper metal

    B

    copper(II) ions

    hydrogen gas

    C

    oxygen gas

    copper metal

    D

    oxygen gas

    hydrogen gas

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      51 mark

      What is the correct half equation for the reaction that takes place at the cathode during the electrolysis of molten zinc(II) chloride?

      • Zn   Zn2+  +  2e-

      • 2Cl- + 2e- ⟶ Cl2

      • Zn2+  +  2e-Zn

      • Cl2 2Cl- + 2e-

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      11 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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      21 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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      31 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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      41 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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      51 mark

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

      • Chlorine

      • Hydrogen

      • Potassium

      • Potassium hydroxide

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      61 mark

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

      • Chloride

      • Chlorine

      • Copper

      • Hydrogen

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      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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      21 mark

      Sodium chloride solution can undergo electrolysis. 

      What product will be formed at the negative electrode?

      • Oxygen

      • Chlorine

      • Hydrogen

      • Sodium

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      31 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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      41 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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      51 mark

      During the electrolysis of brine, a gas is produced at the cathode.

      What is the half-equation for the reaction on the cathode?

      • 2Cl- → Cl2 + 2e-

      • 2Cl- + 2e- → Cl2

      • 2H+ + 2e- → H2

      • 2H+ → H2 + 2e-

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