Practice Questions

List the two main types of batteries and give one example of each.

Recall the value of the standard electrode potential assigned to the Standard Hydrogen Electrode (SHE) at all temperatures.

Formulate the general relationship between the standard Gibbs free energy change ($\Delta_r G^\circ$) and the equilibrium constant ($K_c$) for a cell reaction.

State Faraday's first law of electrolysis.

Justify why alternating current (AC) is used instead of direct current (DC) for measuring the resistance of an electrolytic solution.

Critique the design of a primary battery. What is its fundamental limitation that secondary batteries overcome?

Define a galvanic cell and state its primary function.

Explain the function and importance of a salt bridge in a galvanic cell.

Describe the construction of a Daniell cell and write its cell representation according to IUPAC convention.

Name the cathode, anode, and electrolyte used in a mercury cell.

Identify the relationship between the standard Gibbs energy change ($\Delta_r G^{\circ}$) and the standard cell potential ($E_{\text{cell}}^{\circ}$).

Summarize the key differences between a galvanic cell and an electrolytic cell.

Design a galvanic cell using magnesium and silver electrodes. Formulate the cell notation, write the half-cell and overall cell reactions, and justify why this combination would produce a high cell potential by referencing the standard electrode potential table.

A student proposes using a zinc pot to store a copper sulphate solution. Critique this proposal from an electrochemical standpoint. Justify your conclusion using standard electrode potentials ($E^\circ_{\text{Zn}^{2+}/\text{Zn}} = -0.76 \text{ V}$, $E^\circ_{\text{Cu}^{2+}/\text{Cu}} = +0.34 \text{ V}$).

Critique the statement: "The conductivity of an electrolytic solution always increases upon dilution." Justify your reasoning by differentiating between conductivity ($\kappa$) and molar conductivity ($\Lambda_m$).

You are tasked with designing an industrial process for the electro-refining of impure copper. Create a schematic of the electrolytic cell, specifying the materials for the anode, cathode, and electrolyte. Formulate the electrode reactions and justify why this process results in high-purity copper at the cathode.

Propose an electrochemical method to prevent the rusting of an underground iron pipeline. Justify your method by explaining the underlying electrochemical principles.

Evaluate the effect of doubling the concentration of both $\text{Zn}^{2+}$ and $\text{Cu}^{2+}$ ions on the EMF of a Daniell cell. Justify your answer using the Nernst equation.

Evaluate the feasibility of a reaction between ferrous ions ($\text{Fe}^{2+}$) and bromine ($\text{Br}_2$) under standard conditions. Justify your prediction by calculating the standard cell potential ($E^\circ_{\text{cell}}$) and the standard Gibbs free energy change ($\Delta_r G^\circ$). (Given: $E^\circ_{\text{Fe}^{3+}/\text{Fe}^{2+}} = +0.77 \text{ V}$, $E^\circ_{\text{Br}_2/\text{Br}^-} = +1.09 \text{ V}$).

Explain corrosion of iron as an electrochemical process, identifying the reactions at the anode and cathode.

State Kohlrausch's law of independent migration of ions and write the mathematical expression for it.

Recall the Nernst equation for a general electrode reaction $\text{M}^{n+}(\text{aq}) + ne^- \rightarrow \text{M}(\text{s})$ and explain each term in the equation.

Explain the difference between metallic conductance and electrolytic conductance.

Define resistivity ($\rho$), conductivity ($\kappa$), and molar conductivity ($\Lambda_m$). Explain how conductivity and molar conductivity of an electrolytic solution change with a decrease in concentration.

Propose a method to determine the standard electrode potential of a $\text{Mg}^{2+}|\text{Mg}$ half-cell. Create a diagram of the experimental setup, formulate the cell representation, and explain how the final value would be calculated and interpreted.

Describe the construction and working of a hydrogen-oxygen fuel cell. List the reactions at the anode and cathode.

A galvanic cell is constructed with the following reaction: $\text{Mg(s)} + 2\text{Ag}^+(0.001 \text{ M}) \rightarrow \text{Mg}^{2+}(0.10 \text{ M}) + 2\text{Ag(s)}$. Given $E^\circ_{\text{cell}} = 3.17 \text{ V}$. Evaluate whether the cell potential ($E_{\text{cell}}$) will be greater or less than the standard cell potential ($E^\circ_{\text{cell}}$). Justify your prediction qualitatively using Le Chatelier's principle and quantitatively by calculating the actual $E_{\text{cell}}$ at $298 \text{ K}$ using the Nernst equation.

Design an experiment to determine the molar conductivity at infinite dilution ($\Lambda_m^\circ$) for a weak electrolyte like acetic acid ($\text{CH}_3\text{COOH}$). Justify your choice of strong electrolytes and formulate the necessary calculations based on Kohlrausch's law.

Create a hypothetical fuel cell that uses the combustion of methanol ($\text{CH}_3\text{OH}$) in an acidic medium. Formulate the half-cell reactions at the anode and cathode, and the overall cell reaction. Evaluate its potential advantages and disadvantages compared to the hydrogen-oxygen fuel cell.

Propose a modification to the standard hydrogen electrode (SHE) that would make it more practical for routine laboratory use, while still maintaining its function as a reference electrode. Justify your proposed changes.