Why is the volume of gas collected at the anode lower during electrolysis of acidified water?
Answer and explanation
Correct answer: Oxygen forms at the anode, and the reaction produces 2 mol of H₂ for every 1 mol of O₂.
The overall reaction for electrolysis of acidified water is \(2H_2O(l) \rightarrow 2H_2(g) + O_2(g)\). Oxygen is produced at the anode and hydrogen at the cathode. At the same temperature and pressure, gas volume is proportional to the number of moles, so the volume ratio of hydrogen to oxygen is \(2:1\). Therefore, the oxygen collected at the anode has the lower volume. This difference is due to the stoichiometric ratio in the equation, not to molar mass.
Frequently asked questions
What is the correct answer to this question?
Oxygen forms at the anode, and the reaction produces 2 mol of H₂ for every 1 mol of O₂.
Why is this the correct answer?
The overall reaction for electrolysis of acidified water is \(2H_2O(l) \rightarrow 2H_2(g) + O_2(g)\). Oxygen is produced at the anode and hydrogen at the cathode. At the same temperature and pressure, gas volume is proportional to the number of moles, so the volume ratio of hydrogen to oxygen is \(2:1\). Therefore, the oxygen collected at the anode has the lower volume. This difference is due to the stoichiometric ratio in the equation, not to molar mass.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Chemical Reactions and Equations.
