Question

How to find which reaction will be at anode and cathode?

Answer 1

Oxidation always occurs at anode, for batteries as well as electrolysis. Oxidation occurs when a substance loses electrons.

You can identify oxidation as a reaction in which the oxidation number increases.

For eg, Zn---> Zn2+

or H2---> 2H+

Reduction always occurs at cathode. All metals are deposited at cathode during electrolysis.

You can identify this reaction by decrease in oxidation state.

For eg, Cu+2---> Cu

Ag+---> Ag

Reduction occurs when a substance gains electrons.

Most chemical reactions work in this manner, where both oxidation and reduction takes place and they are called redox reactions.

Hope that helps!