Question 1

Which of the following best describes the function of the salt bridge in a galvanic cell, as shown in the diagram with Cu and Ag electrodes?

Accepted Answer

It maintains electrical neutrality by allowing ions to flow between the half-cells.

Question 2

In the reaction $$\mathrm{Cu(s) + 2Ag^+(aq) \rightarrow Cu$$^{2+}$$(aq) + 2Ag(s)}$$, which species is oxidized and which is reduced?

Accepted Answer

Cu is oxidized, Ag+ is reduced.

Question 3

A student sets up a concentration cell with Zn electrodes in solutions of $$0.10\,\mathrm{M}$$ and $$0.50\,\mathrm{M} Zn$^{2+}. $$What is the cell potential at $$25^\circ\mathrm{C}$$? Use $$E^\circ_{cell} = 0.000\,\mathrm{V}$$ and $$E_{cell} = E^\circ_{cell} - \frac{0.0592}{2} \log \frac{0.10}{0.50}.$$

Accepted Answer

$$+0.021\,\mathrm{V}$$

Question 4

Which equation correctly relates the standard cell potential ($$E^\circ_{cell}$$), the standard free energy change ($$\Delta G^\circ$$), and the equilibrium constant ($$K$$)?

Accepted Answer

$$E^\circ_{cell} = \frac{RT}{nF} \ln K$$

Question 5

In a galvanic cell, which statement about the anode and cathode is correct?

Accepted Answer

Oxidation occurs at the anode and reduction at the cathode.

Question 6

A battery is constructed using the following half-reactions: $$\mathrm{Zn(s) \rightarrow Zn$$^{2+}$$(aq) + 2e^-}$$ ($$E^\circ = -0.7618\,\mathrm{V}) $$and $$\mathrm{Cu$$^{2+}$$(aq) + 2e^- \rightarrow Cu(s)}$$ ($$E^\circ = +0.34\,\mathrm{V}). $$What is the standard cell potential?

Accepted Answer

$$+1.1018\,\mathrm{V}$$

Question 7

Which of the following batteries is most commonly used in smartphones and laptops due to its high energy density and rechargeability?

Accepted Answer

Lithium-ion battery

Question 8

During the electrolysis of molten NaCl, what is produced at the cathode?

Accepted Answer

Sodium metal

Question 9

Which method is commonly used to protect iron structures from corrosion, as shown in the diagram with a sacrificial anode?

Accepted Answer

Attaching a more reactive metal such as magnesium to act as a sacrificial anode.

Question 10

In the electroplating process, which statement is correct?

Accepted Answer

The work piece is the cathode and metal cations are reduced onto its surface.

Question 11

Which of the following statements about the Nernst equation is correct?

Accepted Answer

It is used to calculate cell potentials under non-standard conditions.

Question 12

A student wants to plate 1.00 g of copper from a CuSO$$_4$$ solution using a current of 2.25 A. How many minutes are required? (Cu molar mass = 63.55 g/mol, 2 electrons per Cu atom, 1 Faraday = 96,485 C)

Accepted Answer

22.5 min

Question 13

Which of the following is true for a spontaneous redox reaction in a galvanic cell?

Accepted Answer

$$E^\circ_{cell} is $$positive, $$\Delta G^\circ is $$negative, $$K \u003e 1$$

Question 14

Which species is the cathode in the cell notation: $$\mathrm{Co(s) | Co$$^{2+}$$(aq) || Ce$$^{4+}$$(aq), Ce$$^{3+}$$(aq) | Pt(s)}$$?

Accepted Answer

Ce$$^{4+}(aq)$$

Question 15

Which of the following reactions is most likely to occur spontaneously when an iron nail is placed in a solution of copper sulfate?

Accepted Answer

$$\mathrm{Fe(s) + $$CuSO_4$$(aq) \rightarrow Cu(s) + $$FeSO_4$$(aq)}$$

Question 16

Which of the following is a correct statement about the relationship between cell potential and concentration in a galvanic cell?

Accepted Answer

Increasing the concentration of reactants increases the cell potential.

Question 17

Which of the following is the correct half-reaction for the reduction of oxygen in acidic conditions?

Accepted Answer

$$\mathrm{O_2$(g) + 4 H^+ + 4 e^- \rightarrow 2 H_2O(l)}$$

Question 18

Which of the following statements about fuel cells is correct?

Accepted Answer

Fuel cells continuously produce electricity as long as reactants are supplied.

Electrochemistry: Redox Reactions, Galvanic Cells, and Electrolytic Processes

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