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Reduction at the Cathodes, Oxidation at the Anode - always?

Is it this ALWAYS the case, like for any reaction/electrolysis?

Like for Aluminium electrolysis

At the Cathode its:

Al3+ + 3e- ---> Al [REdcution]

At the Anode:

2O2- - 4e- ----> O2 [Oxidation]

Is it always this?

Thanks!
If you think about it, the cathode is negative so only positively charged ions will be attracted to it, and these will gain electrons which is reduction. In contrast, the anode is positive so only negatively charged ions will be attracted to it, and these will lose electrons which is oxidation. Therefore, the answer to your question is yes, I think!

Note: For your second equation, it's better to write it as: 2O2- ---> 2O2 + 4e- (That's what we've been told anyway)
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irfy
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piece_by_piece
If you think about it, the cathode is negative so only positively charged ions will be attracted to it, and these will gain electrons which is reduction. In contrast, the anode is positive so only negatively charged ions will be attracted to it, and these will lose electrons which is oxidation. Therefore, the answer to your question is yes, I think!

Note: For your second equation, it's better to write it as: 2O2- ---> 2O2 + 4e- (That's what we've been told anyway)


Ahhh thank you!

And ye, in my textbook its written that way too, but I prefer any electron gain/loss to be on the left - any reason why it should be the way you say it?
irfy
Ahhh thank you!

And ye, in my textbook its written that way too, but I prefer any electron gain/loss to be on the left - any reason why it should be the way you say it?


There's no real reason, as far as I'm aware. We've just been told that it's good practice and it says something in my textbook from the exam board that electron loss should be expressed like this.
Be careful with the terminology used for electrolysis cells and electrochemical cells.

In an electrochemical cell the cathode is the positive electrode where reduction occurs, whereas in an electrolytic cell the cathode is the negative electrode where reduction occurs...
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irfy
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charco
Be careful with the terminology used for electrolysis cells and electrochemical cells.

In an electrochemical cell the cathode is the positive electrode where reduction occurs, whereas in an electrolytic cell the cathode is the negative electrode where reduction occurs...


Electrochemical cell is the salt bridge one right? And electrolytic is the AS one
irfy
Electrochemical cell is the salt bridge one right? And electrolytic is the AS one


Electrochemical cell makes electricity (and has salt bridge)
Electrolytic uses electricity to break apart

:yep:

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