Question 1

Which of the following best describes the Faraday constant ($$F) $$and its significance in electrochemistry?

Accepted Answer

It is the charge on one mole of electrons, approximately $$9.6485 	imes 10^4$ C/mol, and is used to relate electrical work to chemical reactions.

Question 2

A voltaic cell does work by moving electrons from one electrode to another. Which equation correctly relates the maximum work ($$W_{max}) to $$the cell potential ($$E_{cell}$$)?

Accepted Answer

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

Question 3

Which of the following reactions is an example of a displacement reaction?

Accepted Answer

$$Zn(s) + 2HCl(aq) \rightarrow H_2$(g) + $$ZnCl_2$$(aq)$$

Question 4

During the combination reaction $$2Na(s) + Cl_2$(g) \rightarrow 2NaCl(s)$$, which species is oxidized and which is reduced?

Accepted Answer

Na is oxidized, Cl is reduced.

Question 5

What is the oxidation number of manganese (Mn) in potassium permanganate ($$KMnO_4$$)?

Accepted Answer

+7

Question 6

In the reaction $$2Zn(s) + 2Ag^+(aq) \rightarrow 2Zn$$^{2+}$$(aq) + 2Ag(s)$$, which statement is correct regarding the electron transfer?

Accepted Answer

Each Zn atom loses two electrons, which are gained by Ag$$^+$$ ions.

Question 7

Which rule is INCORRECT for assigning oxidation numbers?

Accepted Answer

The oxidation number of oxygen is always -2 in all compounds.

Question 8

What is the oxidation number of chromium (Cr) in dichromate ion ($$Cr_2O_7$$^{2-}$$)?

Accepted Answer

+6

Question 9

Which of the following best describes a spectator ion in a redox reaction?

Accepted Answer

An ion that appears unchanged on both sides of the equation and does not participate in the reaction.

Question 10

In the half-reaction $$Fe^{3+}(aq) + 3e$$^- \rightarrow Fe(s)$$, what process is occurring?

Accepted Answer

Reduction, because electrons are gained.

Question 11

A battery is an example of which type of electrochemical cell?

Accepted Answer

Voltaic (galvanic) cell

Question 12

Which of the following reactions is a combustion reaction?

Accepted Answer

$$4Fe(s) + 3O_2(g) \rightarrow 2Fe_2O_3(s)$$

Question 13

In the reaction $$2FeI_3(aq) + 3Mg(s) \rightarrow 2Fe(s) + 3MgI_2(aq)$$, which element is oxidized and which is reduced?

Accepted Answer

Mg is oxidized, Fe is reduced.

Question 14

Which equation correctly relates the standard Gibbs free energy change ($$\Delta G^\circ) to $$the equilibrium constant ($$K$$)?

Accepted Answer

$$\Delta G^\circ = -RT \ln K$$

Question 15

Which of the following statements about oxidation and reduction is correct?

Accepted Answer

Oxidation is the loss of electrons and reduction is the gain of electrons.

Question 16

A student is asked to balance the following redox reaction using the half-reaction method: $$Zn(s) + Ag^+(aq) \rightarrow Zn$$^{2+}$$(aq) + Ag(s). $$What is the correct balanced equation after combining the half-reactions?

Accepted Answer

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

Question 17

Which of the following is the correct oxidation number for oxygen in hydrogen peroxide ($$H_2O_2$$)?

Accepted Answer

-1

Question 18

In the reaction $$2FeI_3(aq) + 3Mg(s) \rightarrow 2Fe(s) + 3MgI_2(aq)$$, what is the role of the iodide ion ($$I^-$$)?

Accepted Answer

It acts as a spectator ion and does not participate in the redox process.

Question 19

Which of the following best explains why the work done by an electrochemical cell is negative?

Accepted Answer

Because the cell does work on the surroundings by creating electron flow.

Electrochemistry and Redox Reactions: Principles, Calculations, and Applications

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