Cell potential Knowledge-Based Practice

Questions

1. 1.

   In a standard galvanic cell formed by coupling two different half-cells, which half-cell undergoes reduction at the cathode?

   • A) The half-cell with the more negative standard reduction potential, because it donates electrons more weakly.
   • B) The half-cell whose standard reduction potential is closest to zero, because it requires the lowest activation energy.
   • C) The half-cell that possesses an inherently negative standard reduction potential, regardless of the other half-cell.
   • D) The half-cell with the more positive standard reduction potential, because it has a greater thermodynamic tendency to gain electrons.
2. 2.

   Which of the following correctly pairs the sign of the standard cell potential ($E^\circ_{\text{cell}}$) with the sign of the standard Gibbs free energy change ($\Delta G^\circ$) for an electrochemical reaction that is spontaneous under standard conditions?

   • A) $E^\circ_{\text{cell}} < 0$ and $\Delta G^\circ < 0$
   • B) $E^\circ_{\text{cell}} > 0$ and $\Delta G^\circ < 0$
   • C) $E^\circ_{\text{cell}} > 0$ and $\Delta G^\circ > 0$
   • D) $E^\circ_{\text{cell}} < 0$ and $\Delta G^\circ > 0$
3. 3.

   As a galvanic cell discharges spontaneously at constant temperature, how does the cell potential ($E_{\text{cell}}$) change as the system approaches chemical equilibrium?

   • A) The cell potential decreases continuously until it reaches 0 V at equilibrium.
   • B) The cell potential remains constant at its initial value until all reactants are fully consumed.
   • C) The cell potential increases progressively as oxidation products accumulate.
   • D) The cell potential drops abruptly to a negative value when half of the reactants are consumed.
4. 4.

   When the stoichiometric coefficients of a balanced reduction half-reaction are doubled, how is its standard reduction potential ($E^\circ$) affected?

   • A) It doubles because twice as many electrons are transferred in the half-reaction.
   • B) It is halved because electric potential is inversely proportional to the stoichiometric amounts.
   • C) It is squared because the equilibrium constant of the half-reaction is squared.
   • D) It remains unchanged because standard reduction potential is an intensive property.
5. 5.

   A standard galvanic cell is constructed using a chromium half-cell ($\text{Cr}^{3+}/\text{Cr}$, $E^\circ = -0.74\text{ V}$) and a silver half-cell ($\text{Ag}^+/\text{Ag}$, $E^\circ = +0.80\text{ V}$). What is the standard cell potential ($E^\circ_{\text{cell}}$) for this cell?

   • A) +0.06 V
   • B) -1.54 V
   • C) +3.14 V
   • D) +1.54 V

Answers and step-by-step solutions appear after you finish the test.