5.1 Define the term electrolysis - NSC Technical Sciences - Question 5 - 2020 - Paper 2
Question 5
5.1 Define the term electrolysis.
5.2 Is the electrolysis of copper(II) chloride a spontaneous or a non-spontaneous reaction?
5.3 Explain the answer to QUESTION 5.... show full transcript
Worked Solution & Example Answer:5.1 Define the term electrolysis - NSC Technical Sciences - Question 5 - 2020 - Paper 2
Step 1
Define the term electrolysis.
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Answer
Electrolysis is the process in which electrical energy is converted into chemical energy. This occurs during the decomposition of an ionic substance when an electric current passes through it.
Step 2
Is the electrolysis of copper(II) chloride a spontaneous or a non-spontaneous reaction?
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Answer
The electrolysis of copper(II) chloride is a non-spontaneous reaction.
Step 3
Explain the answer to QUESTION 5.2.
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Answer
This process requires an external supply of electrical energy to proceed, showing that it does not occur spontaneously. The decomposition of copper(II) chloride when current is applied indicates that energy input is necessary.
Step 4
Write down the FORMULA of an electrolyte used in the cell above.
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Answer
CuCl₂
Step 5
At which electrode will the following observations be made? Write down only ANODE or CATHODE.
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Answer
5.5.1 Gas bubbles are formed.
CATHODE
5.5.2 A brownish deposit is formed.
ANODE
Step 6
Define the term reducing agent.
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Answer
A reducing agent is a substance that is oxidised, meaning it loses electrons during a chemical reaction.
Step 7
For the cell above, write down: Oxidation half-reaction.
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Answer
2Cl⁻ → Cl₂ + 2e⁻
Step 8
For the cell above, write down: Reduction half-reaction.
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Answer
Cu²⁺ + 2e⁻ → Cu
Step 9
For the cell above, write down: Net reaction.
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