Question 1

Which of the following statements best describes a voltaic (galvanic) cell?

Accepted Answer

It produces electric current from a spontaneous chemical reaction.

Question 2

In a voltaic cell, which of the following occurs at the anode?

Accepted Answer

Oxidation and electron loss

Question 3

Given the cell notation: $$\mathrm{Zn}(s) \mid \mathrm{Zn}^{2+}(aq) \parallel \mathrm{Cu}^{2+}(aq) \mid \mathrm{Cu}(s)$$, which half-cell acts as the cathode?

Accepted Answer

Copper electrode

Question 4

Why is a salt bridge necessary in a voltaic cell?

Accepted Answer

To maintain electrical neutrality by allowing ion flow

Question 5

Which of the following best explains why electrons flow from the anode to the cathode in a voltaic cell?

Accepted Answer

The anode has higher electrical potential energy than the cathode.

Question 6

Which of the following is the correct formula for calculating the standard cell potential, $$E^\circ_{cell}$$, for a voltaic cell?

Accepted Answer

$$E^\circ_{cell} = E^\circ_{cathode} - E^\circ_{anode}$$

Question 7

A voltaic cell is constructed using the following half-reactions:

$$\mathrm{Cu}^{2+}(aq) + 2e^- \rightarrow \mathrm{Cu}(s) \quad E^\circ = 0.34\,\mathrm{V}$$

$$\mathrm{Mg}^{2+}(aq) + 2e^- \rightarrow \mathrm{Mg}(s) \quad E^\circ = -2.37\,\mathrm{V}$$

What is the standard cell potential?

Accepted Answer

$$2.71\,\mathrm{V}$$

Question 8

Which of the following is true regarding standard electrode potentials ($$E^\circ$$)?

Accepted Answer

They are intensive properties and do not depend on the amount of substance.

Question 9

The standard hydrogen electrode (SHE) is assigned a potential of:

Accepted Answer

$$0.00\,\mathrm{V}$$

Question 10

Which of the following is the strongest reducing agent based on standard reduction potentials?

A) $$\mathrm{Ni}^{2+}(aq) + 2e^- \rightarrow \mathrm{Ni}(s) \quad E^\circ = -0.23\,\mathrm{V}

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

C$$) $$\mathrm{Ag}^+(aq) + e^- \rightarrow \mathrm{Ag}(s) \quad E^\circ = 0.80\,\mathrm{V}$$

Accepted Answer

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

Question 11

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

Accepted Answer

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

Question 12

If the cell potential for the reaction $$\mathrm{Zn}(s) + 2\mathrm{H}^+(aq) \rightarrow \mathrm{Zn}^{2+}(aq) + \mathrm{H}_2(g) is$$ $$0.76\,\mathrm{V}$$, what is the standard reduction potential for $$\mathrm{Zn}^{2+}$$?

Accepted Answer

$$-0.76\,\mathrm{V}$$

Question 13

Which of the following statements about oxidizing and reducing agents is correct?

Accepted Answer

The more negative the $$E^\circ$$, the stronger the reducing agent.

Question 14

Which of the following is the correct cell notation for a cell with the following half-reactions?

Anode: $$\mathrm{Fe}(s) \rightarrow \mathrm{Fe}^{2+}(aq) + 2e^-$$

Cathode: $$\mathrm{Cu}^{2+}(aq) + 2e^- \rightarrow \mathrm{Cu}(s)$$

Accepted Answer

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

Question 15

Which of the following best describes the direction of cation and anion flow in a voltaic cell with a salt bridge?

Accepted Answer

Cations flow toward the cathode; anions flow toward the anode.

Question 16

Which of the following is true about the sign convention for electrodes in a voltaic cell?

Accepted Answer

The anode is negative and the cathode is positive.

Question 17

A student constructs a voltaic cell using $$\mathrm{Sn}(s)$$ and $$\mathrm{Fe}(s)$$ electrodes. If $$E^\circ_{\mathrm{Fe}^{2+}/\mathrm{Fe}} = -0.44\,\mathrm{V}$$ and $$E^\circ_{\mathrm{Sn}^{2+}/\mathrm{Sn}} = -0.14\,\mathrm{V}$$, what is the standard cell potential?

Accepted Answer

$$0.30\,\mathrm{V}$$

Question 18

Which of the following best explains why the coefficients in half-reactions do not affect the value of the standard electrode potential?

Accepted Answer

Standard electrode potentials are intensive properties.

Electrochemistry: Voltaic Cells, EMF, Standard Electrode Potentials, and Redox Agents

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