Which gas is evolved at the cathode in the chlor-alkali process?
Answer and explanation
Correct answer: Hydrogen
In the chlor-alkali process, brine is electrolysed. At the cathode, water gains electrons and is reduced: 2H2O + 2e− → H2 + 2OH−. Therefore hydrogen gas is evolved at the cathode. Chlorine is produced at the anode by oxidation of chloride ions, while oxygen and carbon dioxide are not the expected cathode products under these conditions.
Frequently asked questions
What is the correct answer to this question?
Hydrogen
Why is this the correct answer?
In the chlor-alkali process, brine is electrolysed. At the cathode, water gains electrons and is reduced: 2H2O + 2e− → H2 + 2OH−. Therefore hydrogen gas is evolved at the cathode. Chlorine is produced at the anode by oxidation of chloride ions, while oxygen and carbon dioxide are not the expected cathode products under these conditions.
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.
