✔ 最佳答案
1. Sodium ion is preferentially discharged because of the presence of mercury liquid because sodium can dissolve in mercury to form a stable mixture.
2. If the electrolyte given is "concentrated" potassium iodide, iodide will be discharged at anode to give brown iodine as concentration effect takes place. The concentration of iodide ions is much greater than hydroxide ions so iodide ions will be discharged instead of hydroxide ions.
i.e. You are right to say that hydroxide ions are stronger reducing agents rather than iodide ions, but you should notice whether there are other factors affecting the discharge of ions - concentration, electrodes used.
3. pH < 7 is called acidic solution. pH > 7 is called alkaline solution. It does not imply that it must be concentrated.
In fact, in public exam, the question will specify whether the solution used is very dilute, dilute or concentrated. Otherwise, it is quite vague.
4. I don't understand what you mean in your last question, please clarify it.
2012-02-24 22:02:35 補充：
Amendment:
1. Sodium ion is preferentially discharged because of the presence of mercury liquid. Sodium can dissolve in mercury to form a stable mixture.
參考: Knowledge is power.
