Consider an electrochemical cell based on the reaction: 2H+(aq) + Sn(s) = Sn2+(aq) + H2(g). Which of the following actions would NOT change the measured cell potential?
lowering the pH in the cathode compartment
addition of more tin metal to the anode compartment
any of the changes listed here will change the measured cell potential.
increasing the pressure of hydrogen gas in the cathode compartment.
increasing the [Sn2+] in the anode compartment
To determine which of the actions listed would NOT change the measured cell potential, let's consider the factors that affect the cell potential in an electrochemical cell.
1. Lowering the pH in the cathode compartment: The cell potential is dependent on the concentration of hydrogen ions (H+) in the cathode compartment. By lowering the pH, you are increasing the concentration of H+ ions, which would increase the cell potential. Therefore, this action would change the measured cell potential.
2. Addition of more tin metal to the anode compartment: In this reaction, tin metal (Sn) is being oxidized to form Sn2+ ions. By adding more tin metal to the anode compartment, you are increasing the concentration of tin metal, which would increase the concentration of Sn2+ ions. Since the cell potential is dependent on the concentrations of the species involved in the reaction, this action would change the measured cell potential.
3. Increasing the pressure of hydrogen gas in the cathode compartment: The reaction involves the production of H2 gas at the cathode. Increasing the pressure of the H2 gas would increase the concentration of H2 gas, which follows the ideal gas law. As a result, the concentration of H+ ions, which are involved in the reaction, would also increase. Therefore, this action would change the measured cell potential.
4. Increasing the [Sn2+] in the anode compartment: Since Sn2+ ions are involved in the reaction, increasing their concentration in the anode compartment would increase the concentration of Sn2+ ions available for the reaction. This would result in a change in the measured cell potential.
Based on this analysis, we can conclude that the action that would NOT change the measured cell potential is "any of the changes listed here will change the measured cell potential."