Electrolysis selective discharge Tamil revision mind map presented as a decision flowchart: the core principle that competing ions are compared by standard reduction potential, the cathode path where the cation with the higher more positive E degree is reduced such as copper-two beating hydrogen, the anode path where the species with the lower more negative E degree is oxidised such as chloride beating water at high concentration despite overpotential effects, and four worked case studies -- electrolysis of acidified water, copper sulfate with copper electrodes for electrorefining, copper sulfate with inert electrodes, and brine with inert electrodes in the chlor-alkali process.