In the chlor-alkali process, what is formed at the cathode during electrolysis of concentrated sodium chloride solution?
Answer and explanation
Correct answer: Hydrogen gas
The chlor-alkali process electrolyses concentrated aqueous sodium chloride, or brine. At the cathode, water is reduced more readily than sodium ions: 2H2O + 2e− → H2 + 2OH−. Therefore hydrogen gas is released at the cathode. Chlorine gas forms at the anode, while sodium hydroxide remains in solution; sodium metal is not deposited from this aqueous solution, and oxygen is not the main cathode product. Hence A is correct.
Frequently asked questions
What is the correct answer to this question?
Hydrogen gas
Why is this the correct answer?
The chlor-alkali process electrolyses concentrated aqueous sodium chloride, or brine. At the cathode, water is reduced more readily than sodium ions: 2H2O + 2e− → H2 + 2OH−. Therefore hydrogen gas is released at the cathode. Chlorine gas forms at the anode, while sodium hydroxide remains in solution; sodium metal is not deposited from this aqueous solution, and oxygen is not the main cathode product. Hence A is correct.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
