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Topic: Question in electrolysis : Precipitation of copper from coppersulfate.  (Read 2457 times)

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Offline Null Hikari

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Hi there, am new to these forums and I need some help with this problem

Calculate the potential needed for copper to start precipitating from a solution containing (0.01 M) of CuSO4 with ((enough H2SO4 for pH to be 4)).

I tried my best doing this (see attached image)
but in the end i doubt i even got the right half reactions.

no data about standard reduction potentials is given within the problem, thus there is no hint to that.

Any help would be appreciated :)

Online Borek

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Re: Question in electrolysis : Precipitation of copper from coppersulfate.
« Reply #1 on: October 09, 2014, 02:25:01 PM »
Question asks only about a potential necessary for the copper half reaction to work, and if no other information is given you should report the potential as measured against the SHE.
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Offline Null Hikari

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Re: Question in electrolysis : Precipitation of copper from coppersulfate.
« Reply #2 on: October 10, 2014, 02:16:11 AM »
if that was the case then what does pH have to do with things?

I do know that pH affects some redox reactions, but in this case where there's only a half reaction then does it even matter?.

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Re: Question in electrolysis : Precipitation of copper from coppersulfate.
« Reply #3 on: October 10, 2014, 03:35:29 AM »
IMHO pH doesn't matter here - acid is added just to prevent copper hydroxide precipitation.

To be sure you may want to check what is the Ksp of Cu(OH)2, and what is the maximum possible concentration of Cu2+ in your solution.
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Offline Null Hikari

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Re: Question in electrolysis : Precipitation of copper from coppersulfate.
« Reply #4 on: October 10, 2014, 10:46:00 AM »
Thanks for your help  :) .

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