Question 1

Which of the following best describes the function of the salt bridge in a galvanic (voltaic) cell?

Accepted Answer

It maintains electrical neutrality by allowing the migration of ions between the two half-cells.

Question 2

In the standard Zn-Cu voltaic cell, which of the following statements is correct regarding the direction of electron flow and the reactions at each electrode?

Accepted Answer

Electrons flow from the zinc anode to the copper cathode; oxidation occurs at the anode.

Question 3

Given the cell notation: $$\mathrm{Zn}(s) \mid \mathrm{Zn}^{2+}(aq) \parallel \mathrm{Cu}^{2+}(aq) \mid \mathrm{Cu}(s)$$, what is the balanced overall cell reaction?

Accepted Answer

$$\mathrm{Zn}(s) + \mathrm{Cu}^{2+}(aq) \rightarrow \mathrm{Zn}^{2+}(aq) + \mathrm{Cu}(s)$$

Question 4

Which of the following is the correct cell notation for a voltaic cell based on the reaction: $$2\mathrm{Ag}^{+}(aq) + \mathrm{Cu}(s) \rightarrow 2\mathrm{Ag}(s) + \mathrm{Cu}^{2+}(aq)$$?

Accepted Answer

$$\mathrm{Cu}(s) \mid \mathrm{Cu}^{2+}(aq) \parallel \mathrm{Ag}^{+}(aq) \mid \mathrm{Ag}(s)$$

Question 5

A hydrogen-copper cell is constructed as shown in the images. If the standard reduction potential for $$\mathrm{Cu}^{2+}(aq) + 2e^- \rightarrow \mathrm{Cu}(s) is$$ $$+0.34\ \mathrm{V}$$ and for $$2\mathrm{H}^{+}(aq) + 2e^- \rightarrow \mathrm{H}_2(g) is$$ $$0.00\ \mathrm{V}$$, what is the standard cell potential ($$E^\circ_{cell}$$)?

Accepted Answer

$$E^\circ_{cell} = 0.34\ \mathrm{V}$$

Question 6

Which of the following species is the strongest oxidizing agent under standard conditions, based on the provided table of standard reduction potentials?

Accepted Answer

$$\mathrm{F}_2(g)$$

Question 7

Consider the following half-reactions and their standard reduction potentials:

$$\mathrm{Fe}^{3+}(aq) + e^- \rightarrow \mathrm{Fe}^{2+}(aq)\ \ \ \ E^\circ = 0.77\ \mathrm{V}$$

$$\mathrm{Zn}^{2+}(aq) + 2e^- \rightarrow \mathrm{Zn}(s)\ \ \ \ E^\circ = -0.76\ \mathrm{V}$$

Which species is the stronger reducing agent?

Accepted Answer

$$\mathrm{Zn}(s)$$

Question 8

A voltaic cell is constructed with the following cell notation:
$$\mathrm{Al}(s) \mid \mathrm{Al}^{3+}(aq) \parallel \mathrm{Cu}^{2+}(aq) \mid \mathrm{Cu}(s)$$
Given $$E^\circ(\mathrm{Al}^{3+}/\mathrm{Al}) = -1.66\ \mathrm{V}$$ and $$E^\circ(\mathrm{Cu}^{2+}/\mathrm{Cu}) = 0.34\ \mathrm{V}$$, what is the standard cell potential?

Accepted Answer

$$E^\circ_{cell} = 2.00\ \mathrm{V}$$

Question 9

Which of the following statements about standard reduction potentials is TRUE?

Accepted Answer

The standard reduction potential is an intensive property and does not depend on the amount of substance.

Question 10

For the reaction $$\mathrm{Cu}^{2+}(aq) + 2\mathrm{I}^-(aq) \rightarrow \mathrm{Cu}(s) + \mathrm{I}_2(s)$$, use the standard reduction potentials $$E^\circ(\mathrm{Cu}^{2+}/\mathrm{Cu}) = 0.34\ \mathrm{V}$$ and $$E^\circ(\mathrm{I}_2/\mathrm{I}^-) = 0.54\ \mathrm{V} to $$determine if the reaction is spontaneous as written under standard conditions.

Accepted Answer

No, because $$E^\circ_{cell} is $$negative.

Question 11

A fuel cell uses the reaction $$2\mathrm{H}_2(g) + \mathrm{O}_2(g) \rightarrow 2\mathrm{H}_2\mathrm{O}(l). If$$ $$n = 4$$ and $$E^\circ_{cell} = 1.23\ \mathrm{V}$$, what is the standard free energy change ($$\Delta G^\circ) $$for this reaction? ($$F = 96,485\ \mathrm{C/mol})$$

Accepted Answer

$$\Delta G^\circ = -475\ \mathrm{kJ}$$

Question 12

Which of the following is the correct cell notation for a cell in which iron is oxidized and silver is reduced?

Accepted Answer

$$\mathrm{Fe}(s) \mid \mathrm{Fe}^{2+}(aq) \parallel \mathrm{Ag}^{+}(aq) \mid \mathrm{Ag}(s)$$

Question 13

If the cell potential ($$E_{cell}) $$for a voltaic cell is measured to be negative, what does this indicate about the cell?

Accepted Answer

The cell is not spontaneous as connected; the electrodes may be reversed.

Question 14

Which of the following best explains why the standard hydrogen electrode (SHE) is assigned a potential of 0.00 V?

Accepted Answer

Because it serves as a universal reference for measuring all other electrode potentials.

Question 15

A student constructs a voltaic cell using $$\mathrm{Mg}(s)$$ and $$\mathrm{Cu}(s)$$ electrodes. Given $$E^\circ(\mathrm{Mg}^{2+}/\mathrm{Mg}) = -2.37\ \mathrm{V}$$ and $$E^\circ(\mathrm{Cu}^{2+}/\mathrm{Cu}) = 0.34\ \mathrm{V}$$, what is the standard cell potential and which metal acts as the anode?

Accepted Answer

$$E^\circ_{cell} = 2.71\ \mathrm{V}$$; Mg is the anode

Question 16

Which of the following changes would increase the cell potential of a standard Zn-Cu voltaic cell?

Accepted Answer

Increasing the concentration of $$\mathrm{Cu}^{2+}(aq)$$ ions.

Question 17

Which of the following is the correct expression for the maximum electrical work ($$w_{max}) $$obtainable from a voltaic cell?

Accepted Answer

$$w_{max} = -nFE_{cell}$$

Electrochemistry: Voltaic Cells, Cell Potentials, and Standard Electrode Potentials

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