Deck 14: Oxidation and Reduction

Question 1

Which substance is the reducing agent in this redox equation?
HF + Cl₂ → F₂ + HCl

A)HF
B)Cl₂
C)F
D)HCl
E)none of these

Answer 1

HF

Question 2

Rust formation is accelerated in the presence of salt water because ________

A)oxygen is easily transported in water.
B)the water traps the oxygen at the surface of the metal.
C)the salt water conducts electricity.
D)chloride ions also oxidize the surface of the metal.

Answer 2

the salt water conducts electricity.

Question 3

Which substance is oxidized in this redox reaction?
Br ⁻ (aq)+ MnO₄ ⁻ (aq)→ Br₂(l)+ Mn²⁺(aq)

A)Br ⁻
B)MnO₄ ⁻
C)Br₂
D)Mn²⁺
E)none of these

Answer 3

Br ⁻

Question 4

Redox reactions involve the transfer of _______.

A)hydrogen
B)oxygen
C)protons
D)electrons

Question 5

Which of these is a characteristic associated with reduction?
I. Losing electrons
II. Gaining hydrogen
III. Losing oxygen

A)I only
B)II only
C)III only
D)II and III
E)I and III

Question 6

Which of these is a characteristic associated with oxidation?
I. Gaining electrons
II. Losing hydrogen
III. Losing oxygen

A)I only
B)II only
C)I and II
D)II and III
E)I, II, III

Question 7

Which of these statements about redox reactions is incorrect ?

A)Oxidation is the loss of oxygen.
B)Oxidation is the loss of electrons.
C)Reduction is the gain of electrons.
D)Oxidation is the loss of hydrogen.
E)Reduction is the gain of hydrogen.

Question 8

Which of these is a redox process?
I. Rusting of iron
II. Respiration
III. Burning hydrocarbons

A)I only
B)III only
C)I and II
D)I and III
E)I, II, and III

Question 9

Which of these is a characteristic associated with reduction?

A)Gaining electrons
B)Gaining hydrogen
C)Losing oxygen
D)All of the above
E)None of the above

Question 10

Which of these substances is the most common oxidizing agent?

A)CO
B)H₃O⁺
C)O₂
D)H₂
E)C

Question 11

Which of these substances is the oxidizing agent?
PbCl₄ + SnCl₂ → PbCl₂ + SnCl₄

A)Pb
B)Sn
C)SnCl₂
D)PbCl₄
E)Cl₂

Question 12

Which of these substances is the oxidizing agent?
2CO + 2NO → 2CO₂ + N₂

A)CO
B)NO
C)CO₂
D)N
E)C

Question 13

Which of these is an application of oxidizing agents?

A)Disinfectants
B)Antiseptics
C)Bleaches
D)Water treatment
E)All of these

Question 14

Which of these is a characteristic associated with oxidation?

A)Gaining electrons
B)Gaining hydrogen
C)Losing oxygen
D)All of the above
E)None of the above

Question 15

Which of these statements about redox reactions is incorrect ?

A)Oxidation is the gain of oxygen.
B)Oxidation is the loss of electrons.
C)Reduction is the gain of electrons.
D)Oxidation is the gain of hydrogen.
E)All of these statements are correct.

Question 16

During oxidation-reduction reactions, the substance which loses electrons is ____ and the substance which gains electrons is ____.

A)oxidized, reduced
B)reduced, oxidized
C)reduced, dissolved
D)reduced, accelerated
E)oxidized, dissolved

Question 17

Which substance is the oxidizing agent in this redox reaction?
Br ⁻ (aq)+ MnO₄ ⁻ (aq)→ Br₂(l)+ Mn²⁺(aq)

A)Br ⁻
B)MnO₄ ⁻
C)Br₂
D)Mn²⁺
E)none of these

Question 18

Which substance is reduced in this redox equation?
HF + Cl₂ → F₂ + HCl

A)HF
B)Cl₂
C)F
D)HCl
E)none of these

Question 19

Which of these pairs are correctly matched?

A)Oxidation = the loss of oxygen
B)Reduction = the reducing agent
C)Oxidation = the loss of electrons
D)Oxidation = the gain of hydrogen
E)Both B and C are correct.

Question 20

Which of these is not an oxidation-reduction reaction?

A)CuO(s)+ H₂(g)→ Cu(s)+ H₂O(l)
B)CO₂(g)+ H₂(g)→ CO(g)+ H₂O(l)
C)I ⁻ (aq)+ NO₃ ⁻ (aq)→ NO(g)+ I₂(s)
D)Mn(OH)₂(s)+ MnO₄ ⁻ (aq)→ MnO₄^{2 −} (aq)
E)HCl(aq)+ NaOH(aq)→ NaCl(aq)+ H₂O (l)

Question 21

Which of these substances is not a reducing agent used in industrial processes?

A)CO
B)H₂
C)O₂
D)C
E)Both C and D

Question 22

Which of these substances are used in the reduction of metal ores?
I. CO
II. C
III. O₂
IV. H₂

A)I only
B)II only
C)III only
D)I and II
E)I, II, and III

Question 23

During photosynthesis ____ is ____ to form glucose and oxygen.

A)carbon, oxidized
B)carbon , reduced
C)water, reduced
D)hydrogen, oxidized
E)oxygen, reduced

Question 24

Which of these substances is oxidized?
Fe₂O₃ + 3CO → 2Fe + CO₂

A)Fe₂O₃
B)CO
C)2Fe
D)C
E)O₂

Question 25

Which of these substances is the reducing agent?
Fe₂O₃ + 3CO → 2Fe + CO₂

A)Fe₂O₃
B)CO
C)2Fe
D)C
E)O₂

Question 26

During respiration sugars are oxidized in the presence of ____ to produce carbon dioxide and water.

A)O₂
B)H₂O
C)C
D)CO
E)H₂

Question 27

During respiration, sugars are ____ in the presence of oxygen to producecarbon dioxide and water.

A)dissolved
B)formed
C)reduced
D)oxidized
E)recycled

Question 28

Which of these are oxidation-reduction reactions?
I. 3H₂ + N₂ → 2NH₃
II. Cu₂O + C → 2Cu + CO
III. Fe₂O₃ + 3CO → 2Fe + CO₂
IV. 2K + Br₂ → 2KBr

A)I only
B)III only
C)I and II
D)I, II, and III
E)all of these

Question 29

Which of these are oxidation-reduction reactions?
I. PCl₃ + 3H₂O → 3HCl + H₃PO₃
II. Fe₂O₃ + 3CO → 2Fe + 3CO₂
III. CaCO₃ + HClO₃ → Ca(ClO₃)₂ + CO₂ + H₂O

A)I only
B)II only
C)I and II
D)I and III
E)I, II, and III

Question 30

Which of these pairs represent the reactants in photosynthesis?

A)Oxygen and carbon dioxide
B)Carbon dioxide and sugars
C)Water and carbon dioxide
D)Oxygen and water
E)Water and sugars

Question 31

Which of these is not used as a topical antiseptic?

A)Hydrogen peroxide
B)Iodine
C)Benzoyl peroxide
D)Chlorine
E)All of these

Question 32

Which of these substances is the most common reducing agent?

A)H₂
B)H₃O⁺
C)O₂
D)H₂O
E)CO

Question 33

The process by which plants generate glucose is known as ____.

A)respiration
B)photosynthesis
C)Haber process
D)digestion
E)rusting

Question 34

Which of these equations correctly represents photosynthesis?

A)3H₂ + N₂ → 2NH₃
B)Cu₂O + C → 2Cu + CO
C)Fe₂O₃ + 3CO → 2Fe + CO₂
D)C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O
E)6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Question 35

Which of these is correctly associated with the cathode?
I. Positive electrode
II. Electrode at which a substance loses electrons
III. Electrode at which reduction occurs

A)I only
B)II only
C)I and II
D)I and III
E)I, II, and III

Question 36

Which of these equations correctly represents the Haber process?

A)3H₂ + N₂ → 2NH₃
B)Cu₂O + C → 2Cu + CO
C)Fe₂O₃ + 3CO → 2Fe + CO₂
D)C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O
E)6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Question 37

Which statement about an electrochemical cell is incorrect ?

A)Reduction occurs at the anode.
B)The salt bridge is made from a porous material.
C)The electrode which acts as the anode carries a negative charge.
D)The current in the external wire always flows from anode to cathode.
E)Any spontaneous reaction can serve as a source of energy in a battery.

Question 38

The series of redox reactions which provide energy for animals is known as ____.

A)respiration
B)photosynthesis
C)Haber process
D)metabolism
E)rusting

Question 39

Which of these pairs represent the products of respiration?

A)Oxygen and carbon dioxide
B)Carbon dioxide and sugars
C)Water and carbon dioxide
D)Oxygen and water
E)Water and sugars

Question 40

Which of these statements about respiration is correct?

A)Carbon is oxidized during respiration.
B)Respiration is an exothermic process.
C)Carbon dioxide and water are produced during respiration.
D)The final step of digestion requires oxygen to oxidize glucose.
E)All of these statements are correct.

Question 41

Which statements about the lead-acid battery is correct?
Pb + PbO₂ + 4H⁺ + SO₄^{2 −} → 2PbSO₄ + 2H₂O

A)Lead is oxidized.
B)Lead oxide acts as the cathode.
C)Both the anode and cathode reactions result in the formation of PbSO₄.
D)Lead and lead oxide can be reformed from lead sulfate with the application of an outside electrical current.
E)All of these statements are correct.

Question 42

Which substance acts as the cathode in the lead-acid automobile battery?
Pb + PbO₂ + 4H⁺ + SO₄^{2 −} → 2PbSO₄ + 2H₂O

A)Pb
B)PbO₂
C)4H⁺
D)SO₄^{2 −}
E)H₂O

Question 43

Which of these processes could occur at the cathode in an electrochemical cell?

A)2Br ⁻ → Br₂+ 2e ⁻
B)Cr → Cr³⁺ + 3e ⁻
C)Cu → Cu²⁺ + 2e ⁻
D)Li⁺ + 1e ⁻ → Li
E)H₂ + 2OH ⁻ → 2H₂O + 2e ⁻

Question 44

Which of these statements correctly explains why batteries run out of energy?

A)The battery solutions boil off.
B)The battery solutions solidify.
C)The battery reactants are used up.
D)The external circuit becomes corroded.
E)The battery salt bridge reacts with the reactants.

Question 45

Which of these is a possible anodic reaction which occurs during the corrosion of iron?

A)2Fe(s)→ 2Fe²⁺(aq)+ 4e ⁻
B)2H⁺(aq)+ 2e ⁻ → H₂(g)
C)2H₂O(l)+ 2e ⁻ → H₂(g)+ 2OH ⁻ (aq)
D)O₂(g)+ 2H₂O(l)+ 4e ⁻ → 4OH ⁻ (aq)
E)SO₂(g)+ O₂(g)+ 2e ⁻ → SO₄^{2 −} (aq)

Question 46

Which of these methods are utilized to help prevent the rusting of iron?
I. Painting iron.
II. Treating iron with sulfuric acid.
III. Coating iron with a metal which is more likely to oxidize.

A)I only
B)II only
C)I and III
D)I, II, and III
E)III only

Question 47

In electrochemical cells ____ occurs at the anode and ____ occurs at the cathode.

A)oxidation, reduction
B)reduction, oxidation
C)oxidation, oxidation
D)gain of mass, reduction
E)loss of mass, oxidation

Question 48

Which of these substances is not found in a common Leclanche dry cell?

A)Zn
B)MnO₂
C)NH₄Cl
D)H₂SO₄
E)C

Question 49

Which of these is not component in the hydrogen-oxygen fuel cell?

A)H₂
B)KOH
C)O₂
D)C
E)Pt

Question 50

Which of these batteries has a continually renewable reactant source?

A)Zinc-copper battery
B)Leclanche dry cell
C)Lead-acid battery
D)Alkaline battery
E)Fuel cells

Question 51

Coating iron with a more oxidative metal than itself to prevent rusting is known as ____.

A)scrubbing
B)galvanizing
C)proofing
D)protecting
E)seal coating

Question 52

The fraction of iron produced in the US to replace rusted iron is approximately ___.

A)1\2
B)1\3
C)1\4
D)1\5
E)1\6

Question 53

Which substance acts as the anode in the lead-acid automobile battery?
Pb + PbO₂ + 4H⁺ + SO₄^{2 −} → 2PbSO₄ + 2H₂O

A)Pb
B)PbO₂
C)4H⁺
D)SO₄^{2 −}
E)H₂O

Question 54

Which of these reactions occurs at the anode in this fuel cell?
2H₂ + O₂ → 2H₂O

A)H₂ + 4OH ⁻ → 4H₂O + 4e ⁻
B)O₂ + 2H₂ O + 4e ⁻ → 4OH ⁻
C)4OH ⁻ + 4H⁺ → 4H₂O
D)4OH ⁻ + 4e − → 4H₂O
E)none of these

Question 55

How many electrons are transferred in the redox reaction of a typical flashlight battery?
Zn + 2MnO₂ + H₂O → Zn²⁺ + Mn₂O₃ + 2OH ⁻

A)1
B)2
C)3
D)4
E)6

Question 56

Which of these is not an advantage of the alkaline battery over the Leclanche dry cell?

A)Longer shelf life
B)Longer battery life
C)More inexpensive
D)Less subject to corrosion
E)All of these are advantages of the alkaline battery over the Leclanche dry cell.

Question 57

Which of these are the primary components in an automobile battery?

A)Lead and water
B)Copper and lead
C)Copper and zinc
D)Lead and sulfuric acid
E)Copper and sulfuric acid

Question 58

Which of these is correctly associated with the anode?
I. Negative electrode
II. Electrode at which a substance loses electrons
III. Electrode at which reduction occurs

A)I only
B)II only
C)I and II
D)I and III
E)I, II, and III

Question 59

Which of these is a possible cathodic reaction which occurs during the corrosion of iron?

A)2Fe(s)→ 2Fe²⁺(aq)+ 4e ⁻
B)2H⁺(aq)+ 2e ⁻ → H₂(g)
C)2H₂O(l)+ 2e ⁻ → H₂(g)+ 2OH ⁻ (aq)
D)O₂(g)+ 2H₂O(l)+ 4e ⁻ → 4OH ⁻ (aq)
E)SO₂(g)+ O₂(g)+ 2e ⁻ → SO₄^{2 −} (aq)

Question 60

Which of these processes could occur at the anode in an electrochemical cell?

A)Br₂ + 2e ⁻ → 2Br ⁻
B)Zn → Zn²⁺ + 2e ⁻
C)Cu²⁺ + 2e ⁻ → Cu
D)Na⁺ + 1e ⁻ → Na
E)Pb⁴⁺ + 2e ⁻ → Pb²⁺

Question 61

Free radicals  _____.

A)are very reactive
B)are very unstable
C)contribute to aging in humans
D)can alter biological molecules
E)all of the above

Question 62

A sliced apple will turn brown when exposed to air _____.

A)oxygen in the air oxidizes the chemicals present in the apple
B)oxygen in the air reduces the chemicals present in the apple
C)nitrogen in the air oxidizes the chemicals present in the apple
D)nitrogen in the air reduces the chemicals present in the apple
E)none of the above

Question 63

Which statement is incorrect ?

A)Zinc is used for galvanization because it loses electrons more easily than iron.
B)Zinc is used for galvanization because it forms a film that protects the iron.
C)Zinc is used for galvanization because it cannot be oxidized.
D)None of the above.

Question 64

Which of these metals are often used to help prevent the rusting of iron?
I. Al
II. Zn
III. Mg
IV. Na

A)I only
B)II only
C)I and III
D)I, II, and IV
E)I, II, and III

Question 65

Which of these is an antioxidant?

A)vitamin E
B)vitamin C
C)beta carotene
D)all of the above
E)none of the above

Question 66

Atoms or molecules with unpaired electrons are called:

A)Inert
B)radiation
C)oxidizers
D)free radicals
E)antioxidants