在Electrolysis of dilute sulpuric acid, 為何在cathode出的物質是Hydrogen?SO4(2-)的oxdizing power不是比H+更強嗎?
不是應該出SO2(aq) or SO3 (2-)(aq)嗎?
Electrolysis of dilute sulpuric acid
2007-09-02 10:09 pm
回答 (2)
2007-09-03 6:12 am
✔ 最佳答案
其實照ECS黎睇, SULPHURIC ACID的確係STRONGER OXIDIZING AGENT THAN H+但邊個係PREFERENTIALLY DISCHARGED要睇埋CONCENTRATION
因為佢地係ECS其實係好近
要睇埋CONCENTRATION
由於係DILUTE
SO SULPHATE ION O既 CONC.低過H+好多
SO H+ DISCHARGE做HYDROGEN GAS
如果用CONCENTRATED SULPHURIC ACID INSTEAD OF DILUTE
咁就會出SO2
希望係你想知O既野LA
參考: MY CHEM KNOWLEDGE
2007-09-02 11:24 pm
Cathode is the place for reduction.
SO4(2-)is reducing agent,so it may be oxidized.
However, H+ is an oxidizing agent. It may be reduced.
So we cannot compare SO4(2-)with H+ because one of them is reducing agent while the other one is oxidizing agent.
In the electrolysis of H2SO4.
AT anode (positively charged), OH- is preferentially discharged
4OH--->O2+4e-+2H2O
AT cathode (negatively charged), H+ is preferentially discharged
2H+ +2e--->H2
SO4(2-)is reducing agent,so it may be oxidized.
However, H+ is an oxidizing agent. It may be reduced.
So we cannot compare SO4(2-)with H+ because one of them is reducing agent while the other one is oxidizing agent.
In the electrolysis of H2SO4.
AT anode (positively charged), OH- is preferentially discharged
4OH--->O2+4e-+2H2O
AT cathode (negatively charged), H+ is preferentially discharged
2H+ +2e--->H2
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