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Can someone explain the conceptual reasoning behind why a concentration cell is available to do work if the concentration of ion in the anode is lower than the concentration of ion in the cathode? Is it because then electron flow will go from anode to cathode to balance out charges?
One thing that's useful for understanding the effect of concentration cells is Le Chatelier's principle. In redox reactions (ie. Zn + 2H+ → Zn2+ + H2), the ion from the oxidation half-reaction (the anode) is a product (Zn2+), and the ion from the reduction half-reaction (the cathode) is a reactant (H+). When you increase the concentration of reactants or decrease the concentration of products, the forward reaction is favored to balance out the change. So this explains why a concentration cell can do work if the concentration of ion in the anode is lower than the concentration of ion in the cathode: when you lower the amount of ion in the anode (lower the amount of product) and you increase the amount of ion in the cathode (increase the amount of reactant), the forward reaction is favored.
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