Electrodes in same beaker (1 Viewer)

[deswa1]

Hey guys,

Can someone explain how the prac on page 88 of Jacaranda works (). Basically, there is a graphite electrode and an electrode of a different metal (e.g. zinc) in the same NaCl electrolyte. It says there is a potential difference because of the different electrodes but I can't see where the oxidation and reducation reactions are taking place.

Cheers,
George

 

[animerocker]

the metal that has a higher reactivity is the anode otherwise known as the electrode undergoing oxidation.
oxidation means its losing ions hence electrons are passing through the wire thus you get a potential difference or voltage as it transfers to the cathode ( reduced metal)
In this example the different metal is the anode which is reacting with the electrolyte soln which means its losing electrons and becoming an ion. Those electrons are transferred to the cathode(graphite).
OILRIG - OIL means Oxidation is losing electrons
RIG means Reduction is gaining electrons
Hopes that help I just finished studying the galvanic cell yesterday at school so there will be some potential errors and poor communication of the knowledge.

 

[deswa1]

I understand all that about the anode and cathode but what I don't is where the reduction occurs. I think the zinc is the anode, so it loses electrons (oxidation) but I don't get where those electrons go. As graphite is inert, it can't be reduced, and the sodium in the NaCl solution is more reactive than the zinc so I don't think it can be reduced either.

 

[BadMeetsEvil]

Hey guys,

Can someone explain how the prac on page 88 of Jacaranda works (View attachment 23626). Basically, there is a graphite electrode and an electrode of a different metal (e.g. zinc) in the same NaCl electrolyte. It says there is a potential difference because of the different electrodes but I can't see where the oxidation and reducation reactions are taking place.

Cheers,
George

this means that ions are displaced from or in the solution. which means that the redox reaction occurs between the ions in solution and the test metal. so in your case, find whether chloride or zink is higher in the standard reduction potential table and whatever is higher oxidizes. graphite is inert and merely conducts the electrons

 

[onytae]

who are you?

 

[deswa1]

This is George. Who are you?