9.1 Define the term electrolysis - NSC Physical Sciences - Question 9 - 2022 - Paper 2
Question 9
9.1 Define the term electrolysis.
9.2 Chlorine gas, Cl₂(g), is released at electrode X.
Write down the:
9.2.1 Letter (X or Y) of the electrode where oxidation... show full transcript
Worked Solution & Example Answer:9.1 Define the term electrolysis - NSC Physical Sciences - Question 9 - 2022 - Paper 2
Step 1
Define the term electrolysis.
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Answer
Electrolysis is the chemical process in which electrical energy is converted to chemical energy. It involves the decomposition of an ionic compound through the use of electrical energy.
Step 2
Letter (X or Y) of the electrode where oxidation takes place.
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Answer
X
Step 3
Half-reaction that takes place at electrode Y.
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Answer
2H₂O(l) + 2e⁻ → H₂(g) + 2OH⁻(aq)
Step 4
Direction in which electrons flow in the external circuit.
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Answer
From X to Y
Step 5
Balanced equation for the net (overall) cell reaction that takes place in the cell.
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Answer
2NaCl(aq) + 2H₂O(l) → Cl₂(g) + H₂(g) + 2NaOH(aq)
Step 6
How will the pH of the electrolyte change during the reaction?
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Answer
DECREASES
Step 7
Give a reason for the answer to QUESTION 9.2.
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Answer
The decrease in pH occurs because hydroxide ions are produced at electrode Y, leading to the solution becoming more acidic as chlorine gas is released at electrode X.
