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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: StringFever on September 26, 2009, 09:14:31 am

Title: Electrolysis - the cathode
Post by: StringFever on September 26, 2009, 09:14:31 am

Hi guys,

I was at a TSFX lecture yesterday, and I know they usually go overboard with the stuff that they teach; but Irena, the lecturer, mentioned that in electrolytic cells, never ever consider the cathode as being able to react (or something to that extent).

Could anyone please explain why?

Title: Re: Electrolysis - the cathode
Post by: Edmund on September 26, 2009, 10:32:19 am

Reduction occurs at the cathode. Our aim is to have electrons from the anode to move to the cathode, therefore balancing the positive ions at the cathode solution. We don't want the electrons to react with the electrode, otherwise the solution at the cathode will contain the positive ions. So we use something unreactive like Platinum...

Title: Re: Electrolysis - the cathode
Post by: chem-nerd on September 26, 2009, 01:33:19 pm

Electrolysis is usually used for obtaining pure metals (eg Hall-Heroult cell for Al) or for electroplating an object (eg silver plating a spoon). The cathode needs to be inert or less reactive in order for the desired reaction to take place.