The most interesting process in electrochemical reactions is the transfer of electrons, which is also the reason why the reaction can take place.
Under given conditions, we can easily determine whether a certain reaction can occur by comparing the electrode potentials. But sometimes, although the result of the electron transfer is clear, the specific reaction is often not written or written incorrectly, right?
For water problems, there are probably the following techniques.
First, refer to the reaction conditions. Certain reactions clearly need to be carried out under acidic or alkaline conditions. Such reactions usually involve water or produce water.
The second is to write equations in strict accordance with the requirements. That is, write the half-reaction first. During the process of writing the half-reaction, you will know si participation and generation of H+, OH- or H2O are necessary. Because you need to find the source and destination of each item.
The third is if you really can't figure it out or time doesn't allow it. Then guess when you find that a reaction cannot be balanced, you should consider adding water to the left or right side of the equation to see how adding water can balance it.