![]() The net reaction in a concentration cell is: a+M (cathode, x M) Ma+ (anode, y M). concentration is sought in a chemical analysis.Compare with cathode.The electrode at which oxidation occurs in a cell. Equilibrium for a concentration cell is reached ( 0) when the ion concentrations in the two compartments are equal. Concentration cells are a kind of galvanic cell, but the main difference is that the species on both sides (anode and. (Water is omitted for clarity.) The standard potential of the SHE is arbitrarily assigned a value of 0 V.Īlthough it is impossible to measure the potential of any electrode directly, we can choose a reference electrode whose potential is defined as 0 V under standard conditions. The cell produces a voltage as long as the ion concentrations are different. Galvanic cells work because there is usually a species on the cathode side that has a higher positive potential that pulls electrons over to that side, allowing it to be reduced and the species on the anode side to be oxidized. In the molecular view, the Pt surface catalyzes the oxidation of hydrogen molecules to protons or the reduction of protons to hydrogen gas. Therefore, a concentration cell acts to dilute the more concentrated solution and concentrate the more dilute solution, creating a voltage as the cell reaches. The SHE consists of platinum wire that is connected to a Pt surface in contact with an aqueous solution containing 1 M H + in equilibrium with H 2 gas at a pressure of 1 atm.
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