Chem Come on~

2007-05-22 7:02 am

I want to ask about chemical cellls and electrolysis

first, the conc of ions in the solution will affect the discharge of ions

For anions OH- discharge first usually

when Br-and I- are conc. , they discharge first or OH- discharge first?

My notes said that Br- and I- will be discharged first to OH- in dilute solution

But i did a ex. , it said that when I- is conc. it discharge first than OH-

why?and when OH- compare with I- and Br- will discharge first ?

回答 (1)

Chi Ho

2007-05-22 10:34 pm

✔ 最佳答案

first of all
you know there is a concentration effect on ions discharging
and this effect will happen if I- and Br- are present in the electrolyte
in very dilute solution containing OH- and I-/Br-
OH- will discharge first
it's because OH- is a stronger reducing agent than I-/Br-
so it will discharge first at the anode
for a solution containing OH- and I- with molarity greater 0.1M
I- will discharge first
it's because this concentration of I- makes the discharge of I- more favourable
for a solution containing OH- and Br- with molarity greater than 0.5M
Br- will discharge first
it's because this concentration of Br- makes the discharge of Br- more favourable

參考: me*

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