
Jesse E. answered 10/02/19
Masters in Chemistry and Bachelors in Biology
The definition of electrolysis is using electric current to drive a chemical reaction. For example, in the electrolysis of water,
2 H2O -> 2 H2 + O2
This can be broken down into a reduction and oxidation half-reactions that occur at the Cathode and Anode, respectively:
Reduction Gain Electrons 2 H2O(l) + 2e- -> H2(g) + 2OH-(g)
Oxidation Lose Electrons 2 H2O(l) -> 4e- + 4 H(aq)+ O2(g)
These half-reactions can be completed once you have a balanced reaction. As Chemistry follows a set of rules, the reduction half-reaction will proceed on the cathode and the oxidation half-reaction will proceed on the anode.
If you have any questions, please feel free to let me know!

Jesse E.
For a reference, visit this free online resource: https://chem.libretexts.org/Under_Construction/Purgatory/Core_Construction/Chemistry_30/Electrochemistry/3.3_Electrolysis_of_Water10/02/19