標題: [Chem] HKCEE CHEM Q THANK YOU [打印本頁] 作者: star1105 時間: 2016-4-4 01:41 AM 標題: HKCEE CHEM Q THANK YOU
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why are Zn ions discharged instead of H+? 作者: star1105 時間: 2016-4-4 10:04 AM
em46 em46 作者: inkink 時間: 2016-4-10 12:22 PM
Basically, it is because the question say so.
The flow chart shows zinc is extracted from the solution, so just let the zinc ion reduced at cathode.
The reason behind is about the concentration:
In a basic solution, the concentration of H+ is very, very small. With a much larger concentration of zinc ions available and sufficient potential to make either reaction occur, the zinc reaction is far more likely by numbers alone. Both reactions ought to occur, though the H+ reaction will be very slow due to its low concentration.
