Question 1

Which of the following best describes the fundamental process occurring in a hydrogen–oxygen fuel cell?

Accepted Answer

Hydrogen atoms lose electrons to oxygen atoms, and the electrons are forced through an external circuit, generating electricity.

Question 2

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 3

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

Accepted Answer

Mg is oxidized; Cu is reduced.

Question 4

Which of the following is the correct order of steps for balancing a redox reaction in acidic solution using the half-reaction method?

Accepted Answer

Assign oxidation states, separate into half-reactions, balance all elements except H and O, balance O by adding $$\mathrm{H_2O}$$, balance H by adding $$\mathrm{H^+}$$, balance charge by adding electrons, equalize electrons, add half-reactions.

Question 5

A voltaic cell is constructed using zinc and copper electrodes. Which of the following statements is TRUE?

Accepted Answer

Oxidation occurs at the zinc electrode (anode), and reduction occurs at the copper electrode (cathode).

Question 6

Which of the following metals would NOT dissolve in hydrochloric acid, based on the activity series?

Accepted Answer

Gold

Question 7

What is the role of the salt bridge in a voltaic cell?

Accepted Answer

It allows ions to flow between the half-cells, maintaining electrical neutrality.

Question 8

Which of the following best explains why aluminum does not corrode as rapidly as iron?

Accepted Answer

Aluminum forms a protective oxide layer that prevents further oxidation.

Question 9

Which of the following is a correct statement about the use of a sacrificial anode to prevent corrosion?

Accepted Answer

The sacrificial anode is oxidized in place of the protected metal.

Question 10

Which of the following is a real-world application of electrolysis?

Accepted Answer

Plating silver onto a less expensive metal.

Question 11

In the context of batteries, what does it mean when a battery is 'dead'?

Accepted Answer

The reactants have been depleted and the products have accumulated, so the redox reaction can no longer occur.

Question 12

Which of the following best describes the difference between a voltaic cell and an electrolytic cell?

Accepted Answer

A voltaic cell generates electrical current from a spontaneous redox reaction, while an electrolytic cell uses electrical current to drive a nonspontaneous redox reaction.

Question 13

Which of the following is the correct oxidation state for chromium in $$\mathrm{Cr_2O_7$$^{2-}$$}$$?

Accepted Answer

$$+6$$

Question 14

Which of the following reactions is an example of a redox reaction central to life on Earth?

Accepted Answer

The reduction of carbon during photosynthesis.

Question 15

A breathalyzer fuel cell oxidizes ethyl alcohol at the anode. What is the significance of the current produced?

Accepted Answer

It is proportional to the amount of alcohol in the breath, which correlates to blood alcohol level.

Question 16

Which of the following best describes the role of hydrogen peroxide in hair bleaching?

Accepted Answer

It acts as an oxidizing agent, removing electrons from melanin and thiol groups.

Question 17

Which of the following is a correct application of the activity series?

Accepted Answer

A metal higher on the activity series will spontaneously oxidize in the presence of ions of a metal lower on the series.

Question 18

Which of the following is the correct mnemonic for remembering oxidation and reduction?

Accepted Answer

OIL RIG—Oxidation Is Loss (of electrons); Reduction Is Gain (of electrons)

Question 19

Which of the following is NOT a method for preventing the corrosion of iron?

Accepted Answer

Allowing the iron to remain exposed to water and air.

Chapter 16: Oxidation and Reduction – Introductory Chemistry Study Guide

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