Concentration and Reduction

[Samantha Low 3D]

In a concentration cell, why does reduction take place at the electrode in contact with the higher concentration?

[Alisa Nagashima 1B]

At the cathode end, ions in solution gain electrons as they become part of the solid metal thereby decreasing the concentration of ions in solution. Since we have a high concentration, this is what we want because reactions want to reach equilibrium. At the anode end, the neutral atoms in the solid metal lose electrons so the ion concentration would increase (not what we want since we already have a high concentration and are trying to get to equilibrium)

[Neel Bonthala 2G]

Hey! You can also think about products vs reactants in a concentration cell in terms of diffusion. Molecules in higher concentration regions move to regions of lower concentration. Thus, the reactants move from a region of high concentration to a region of low concentration as products.