Chlorine is produced industrially by the electrolysis of a concentrated sodium chloride solution, NaCl(aq) - NSC Physical Sciences - Question 9 - 2019 - Paper 2
Question 9
Chlorine is produced industrially by the electrolysis of a concentrated sodium chloride solution, NaCl(aq).
The balanced equation for the net (overall) cell reactio... show full transcript
Worked Solution & Example Answer:Chlorine is produced industrially by the electrolysis of a concentrated sodium chloride solution, NaCl(aq) - NSC Physical Sciences - Question 9 - 2019 - 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 using electrical energy to drive a non-spontaneous chemical reaction.
Step 2
Half-reaction that takes place at the cathode.
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Answer
The half-reaction occurring at the cathode can be represented as:
2H2O(l)+2e−→H2(g)+2OH−(aq)
Step 3
NAME or FORMULA of the oxidising agent.
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Answer
The oxidising agent in this reaction is Chlorine (Cl2), which is produced from the oxidation of chloride ions (Cl⁻).
Step 4
Refer to the Table of Standard Reduction Potentials to explain why sodium ions are not reduced during this process.
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Answer
Sodium ions (Na⁺) are not reduced because water has a higher reduction potential than sodium ions. The standard reduction potential of the reaction for water is more favorable than that for sodium reduction, making it preferential for water to be reduced to hydrogen gas instead of sodium ions being reduced to sodium metal.
