Deck 18: Oxidation-Reduction Reactions and Electrochemistry

Question 1

Reduction is a gain of electrons.

Answer 1

True

Question 2

The oxidation state of sulfur in is

A) +6
B) +2
C) +4
D) 0
E) +8

Answer 2

+6

Question 3

In the reaction 2Ca(s) + O₂(g) $\rightarrow$ 2CaO(s), the calcium is ________.

A) oxidized
B) electrolyzed
C) synthesized
D) reduced
E) none of these

Answer 3

oxidized

Question 4

The oxidation state of chlorine in ClO^- is

A) -2
B) -1
C) 0
D) +1
E) +2

Question 5

Which of the following compounds contains oxygen with an oxidation state of -2?

A) Na₂CO₃
B) TiO
C) KOH
D) Li₃PO₄
E) All of the compounds contain oxygen with an oxidation state of -2.

Question 6

What is the oxidation state of copper in CuSO₃ is

A) +2
B) -2
C) 0
D) +1
E) -1

Question 7

Consider the following reaction: Ba + Cl₂ $\rightarrow$ BaCl₂
Which of the following statements is false?

A) The barium atom is losing electrons; therefore, it is oxidized.
B) The chlorine atom is gaining electrons; therefore, it is oxidized.
C) The barium atom is gaining electrons; therefore, it is oxidized.
D) The chlorine atom is losing electrons; therefore, it is reduced.
E) none of these

Question 8

The oxidation state of phosphorus in Mg₃(PO₄)₂ is

A) 0
B) +2
C) +4
D) +5
E) +6

Question 9

The oxidation state of oxygen in O₂ is

A) -2
B) -1
C) 0
D) -4
E) +4

Question 10

The oxidation state of titanium in TiO is

A) +2
B) +1
C) 0
D) -1
E) -2

Question 11

What is the oxidation state of Cr in Cr₂O₇^2-?

A) +12
B) +6
C) +3
D) 0
E) -2

Question 12

In the reaction 2Sr(s) + F₂(g) $\rightarrow$ 2SrF(s), the fluorine is ________.

A) reduced
B) electrolyzed
C) galvanized
D) oxidized
E) none of these

Question 13

The oxidation state of silicon in SiO₂ is

A) +4
B) +2
C) 0
D) -2
E) -4

Question 14

The oxidation state of Rb in any compound is

A) +2
B) +1
C) 0
D) -1
E) -2

Question 15

The oxidation state of Ba in any compound is

A) 0
B) +1
C) +2
D) +3
E) +4

Question 16

The oxidation state of chlorine in MgCl₂ is

A) -1
B) +1
C) 0
D) -2
E) +2

Question 17

The oxidation state of sulfur in H₂SO₄ is

A) +6
B) +4
C) +2
D) +8
E) 0

Question 18

The oxidation state of oxygen in Li₂CO₃ is

A) -2
B) 0
C) +2
D) +4
E) +6

Question 19

The oxidation state of manganese in is

A) 0
B) +3
C) +4
D) +7
E) +8

Question 20

The oxidation state of sulfur in Li₂SO₃ is

A) +4
B) +6
C) +2
D) -2
E) 0

Question 21

The oxidation state of nitrogen in NH₄Cl is

A) +1
B) +3
C) -3
D) -4
E) -2

Question 22

What is the oxidation state of oxygen in Fe₂(CO₃)₃?

A) +4
B) +3
C) +2
D) 0
E) -2

Question 23

In the reaction P₄(s) + 10Cl₂(g) $\rightarrow$ 4PCl₅(s), phosphorus is ______________.

A) reduced
B) electrolyzed
C) synthesized
D) oxidized
E) none of these

Question 24

Which statement is true of the following reaction? 2K + CuCl₂ $\rightarrow$ 2KCl + Cu

A) Copper is reduced.
B) Chlorine is reduced.
C) Potassium is reduced.
D) Copper is oxidized.
E) Chlorine is oxidized.

Question 25

The following reaction occurs in aqueous acid solution: NO₃^- + I^- $\rightarrow$ IO₃^- + NO₂
The oxidation state of iodine in IO₃^- is

A) 0
B) +3
C) -3
D) +5
E) -5

Question 26

The oxidation state of chlorine in Cl₂ is

A) 0
B) +1
C) -1
D) -2
E) none of these

Question 27

Answer the questions that refer to the following reaction:
TiCl₄(l) + O₂(g) $\rightarrow$ TiO₂(s) + 2Cl₂(g)

-Which species is oxidized?

A) Ti
B) Cl
C) O
D) TiO₂
E) O₂

Question 28

What is the oxidation state of carbon in Fe₂(CO₃)₃?

A) +4
B) +3
C) +2
D) 0
E) -2

Question 29

In the reaction P₄(s) + 10Cl₂(g) $\rightarrow$ 4PCl₅(s), chlorine is ______________.

A) oxidized
B) reduced
C) synthesized
D) electrolyzed
E) none of these

Question 30

Answer the questions that refer to the following reaction:
SiO₂(s) + 2C(s) $\rightarrow$ Si(s) + 2CO(g)

-Which species is reduced?

A) Si
B) C
C) O
D) CO
E) SiO₂

Question 31

In which of the following does nitrogen have an oxidation state of +4?

A) HNO₃
B) NO₂
C) N₂O
D) NH₄Cl
E) NaNO₂

Question 32

In reacting, metal atoms characteristically

A) become anions
B) lose electrons
C) decrease in oxidation state
D) form covalent bonds

Question 33

What is the oxidation state of bromine in NH₄Br?

A) -4
B) -2
C) -1
D) 0
E) +1

Question 34

What is the oxidation state of iron in Fe₂(CO₃)₃?

A) +4
B) +3
C) +2
D) 0
E) -2

Question 35

Answer the questions that refer to the following reaction:
SiO₂(s) + 2C(s) $\rightarrow$ Si(s) + 2CO(g)

-Which species is the oxidizing agent?

A) Si
B) C
C) O
D) SiO₂
E) CO

Question 36

The oxidation state of oxygen in Na₂CrO₄ is

A) +1
B) +3
C) +7
D) +5
E) none of these

Question 37

In the reaction N₂(g) + 3H₂(g) $\rightarrow$ 2NH₃(g), nitrogen is ______________.

A) oxidized
B) reduced
C) synthesized
D) electrolyzed
E) none of these

Question 38

The oxidation state of carbon in CH₄ is

A) +4
B) -4
C) +2
D) -2
E) none of these

Question 39

The oxidation state of carbon in CO₂ is

A) +4
B) -4
C) +2
D) -2
E) none of these

Question 40

Answer the questions that refer to the following reaction:
TiCl₄(l) + O₂(g) $\rightarrow$ TiO₂(s) + 2Cl₂(g)

-Which species is the reducing agent?

A) Ti
B) Cl
C) O
D) TiCl₄
E) O₂

Question 41

Balance the following half-reaction that occurs in acidic solution:
NO₃^-(aq) $\rightarrow$ NO₂(g)

Question 42

Balance the following half-reaction that occurs in acidic solution:
MnO₄^-(aq) $\rightarrow$ Mn²⁺(aq)

Question 43

In the reaction C(s) + O₂(g) $\rightarrow$ CO₂(g), carbon is ______________.

A) reduced
B) electrolyzed
C) synthesized
D) oxidized
E) none of these

Question 44

Balance the following reaction that takes place in acidic solution:
Mn(s) + NO₃^-(aq) $\rightarrow$ Mn²⁺(aq) + NO₂(g)

Question 45

Answer the following questions that refer to the unbalanced reaction shown below as it occurs in acidic solution:
_______ Cr₂O₇^2- (aq) + _______ I^-(aq) $\rightarrow$ _______ Cr³⁺(aq) + _______ I₂(s)

-Determine the coefficient for the Cr³⁺ ions.

A) 1
B) 2
C) 3
D) 6
E) 7

Question 46

Of the following four reactions, how many are oxidation-reduction reactions? NaOH + HCl $\rightarrow$ NaCl + H₂O
Cu + 2AgNO₃ $\rightarrow$ 2Ag + Cu(NO₃)₂
Mg(OH)₂ $\rightarrow$ MgO + H₂O
N₂ + 3H₂ $\rightarrow$ 2NH₃

A) 0
B) 1
C) 2
D) 3
E) 4

Question 47

Which of the following are oxidation-reduction reactions? I. PCl₃ + Cl₂ $\rightarrow$ PCl₅
II) Cu + 2AgNO₃ $\rightarrow$ Cu(NO₃)₂ + 2Ag
III) CO₂ + 2LiOH $\rightarrow$ Li₂CO₃ + H₂O
IV) FeCl₂ + 2NaOH $\rightarrow$ Fe(OH)₂ + 2NaCl

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

Question 48

Balance the following reaction that takes place in acidic solution:
I^-(aq) + IO₃^- (aq) $\rightarrow$ I₃^-(aq)

Question 49

Balance the following reaction that takes place in acidic solution:
Cu(s) + NO₃^-(aq) $\rightarrow$ Cu²⁺(aq) + NO(g)

Question 50

Answer the following questions that refer to the unbalanced reaction shown below as it occurs in acidic solution:
_______ Cr₂O₇^2- (aq) + _______ I^-(aq) $\rightarrow$ _______ Cr³⁺(aq) + _______ I₂(s)

-Determine the coefficient for the iodide ions.

A) 1
B) 2
C) 3
D) 6
E) 7

Question 51

In the following reaction, which element is oxidized? 8NaI + 5H₂SO₄ $\rightarrow$ 4I₂ + H₂S + 4Na₂SO₄ + 4H₂O

A) sodium
B) iodine
C) sulfur
D) hydrogen
E) oxygen

Question 52

Balance the following half-reaction that occurs in acidic solution:
SO₃^2-(aq) $\rightarrow$ SO₄^2-(aq)

Question 53

In the following reaction, which species is the reducing agent? 3Cu + 6H⁺ + 2HNO₃ $\rightarrow$ 3Cu²⁺ + 2NO + 4 H₂O

A) H⁺
B) Cu
C) N in NO
D) Cu²⁺
E) N in HNO₃

Question 54

Which of the following statements is/are true? Oxidation and reduction

A) cannot occur independently of each other
B) accompany all chemical changes
C) describe the loss and gain of electron(s), respectively
D) result in a change in the oxidation states of the species involved
E) a, c, and d are true.

Question 55

Answer the following questions that refer to the unbalanced reaction shown below as it occurs in acidic solution:
_______ Cr₂O₇^2- (aq) + _______ I^-(aq) $\rightarrow$ _______ Cr³⁺(aq) + _______ I₂(s)

-Determine the coefficient for water in the balanced equation for the reaction.

A) 1
B) 2
C) 3
D) 6
E) 7

Question 56

In the reaction shown below, which species is oxidized? 2KI + F₂ $\rightarrow$ 2KF + I₂

A) I^-
B) K⁺
C) F₂
D) F^-
E) I₂

Question 57

In the reaction Mg + H₂SO₄ $\rightarrow$ MgSO₄ + H₂, which element, if any, is oxidized?

A) magnesium
B) hydrogen
C) sulfur
D) oxygen
E) None is oxidized.

Question 58

Balance the following reaction that takes place in acidic solution:
Mg(s) + HCl(aq) $\rightarrow$ MgCl₂(aq) + H₂(g)

Question 59

Which of the following reactions does not involve oxidation-reduction?

A) CH₄ + 3O₂ $\rightarrow$ 2H₂O + CO₄
B) Zn + 2HCl $\rightarrow$ ZnCl₂ + H₂
C) 2Na + 2H₂O $\rightarrow$ 2NaOH + H₂
D) MnO₂ + 4HCl $\rightarrow$ Cl₂ + 2H₂O + MnCl₂
E) All are oxidation-reduction reactions.

Question 60

Balance the following half-reaction that occurs in acidic solution:
IO₃^- (aq) $\rightarrow$ I₃^-(aq)

Question 61

Which of the following is true for a galvanic cell based on the following reaction? Zn(s) + Cu²⁺(aq) $\rightarrow$ Zn²⁺(aq) + Cu(s)

A) The zinc is being reduced.
B) The zinc serves as the anode.
C) The Cu²⁺ ion is being reduced.
D) The Cu serves as the anode.
E) two of these

Question 62

In a car battery, which of the following is the electrolyte?

A) Pb(s)
B) PbO₂(s)
C) PbSO₄(s)
D) H₂SO₄(aq)
E) none of these

Question 63

Which of the following statements is not true of electrolysis?

A) Electrolysis is a process where electrical energy is used to produce a chemical change.
B) Electrolysis involves forcing a current through a cell to produce a change that would otherwise not occur.
C) The electrolysis of water produces hydrogen gas and oxygen gas.
D) Electrolysis is used to recharge a lead storage battery.
E) None of these; that is, all these statements are true.

Question 64

Most metals oxidize in air more slowly than expected because

A) a thin layer of the metal oxide forms on the metal surface, thus inhibiting corrosion
B) cathodic protection naturally occurs
C) corrosion occurs only under water
D) the concentration of oxygen in the atmosphere is not high enough
E) none of these

Question 65

The following reaction occurs in aqueous acid solution: NO₃^- + I^- $\rightarrow$ IO₃^- + NO₂
In the balanced equation, the coefficient of water is

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

Question 66

For the redox reaction 2Fe²⁺ + Cl₂ $\rightarrow$ 2Fe³⁺ + 6Cl^-, which of the following are the correct half-reactions?
(I) Cl₂ + 2e^- $\rightarrow$ 2Cl^-
(II) Cl $\rightarrow$ Cl^- + e^-
(III) Cl₂ $\rightarrow$ 2Cl^- + 2e^-
(IV) Fe²⁺ $\rightarrow$ Fe³⁺ + e^-
(V) Fe²⁺ + e^- $\rightarrow$ Fe³⁺

A) I and IV
B) I and V
C) II and IV
D) II and V
E) III and IV

Question 67

Which of the following battery types is commonly used in an automobile?

A) dry cell
B) alkaline dry cell
C) lead storage
D) mercury cell
E) nickel-cadmium

Question 68

In the balanced equation for the following redox equation, what is the sum of the coefficients? Fe³⁺ + I^- $\rightarrow$ Fe²⁺ + I₂

A) 4
B) 5
C) 6
D) 7
E) 8

Question 69

Answer the following questions for a galvanic cell that employs the reaction
2Na(l) + S(l) $\rightarrow$ Na₂S(s)

-What element serves as the cathode?

Question 70

For the reaction of sodium bromide with chlorine gas to form sodium chloride and bromine, the appropriation half-reactions are (ox = oxidation and re = reduction)

A) ox: Cl₂ + 2e^- $\rightarrow$ 2Cl^- re: 2Br^- $\rightarrow$ Br₂ + 2e^-
B) ox: 2Br^- $\rightarrow$ Br₂ + 2e^- re: Cl₂ + 2e^- $\rightarrow$ 2Cl^-
C) ox: Cl + e^- $\rightarrow$ Cl^- re: Br $\rightarrow$ Br^- + e^-
D) ox: Br + 2e^- $\rightarrow$ Br^- re: 2Cl^- $\rightarrow$ Cl₂ + 2e^-
E) ox: 2Na⁺ + 2e^- $\rightarrow$ 2Na re: 2Cl^- $\rightarrow$ Cl₂ + 2e^-

Question 71

Answer the following questions for a galvanic cell that employs the reaction
2Na(l) + S(l) $\rightarrow$ Na₂S(s)

-What element is reduced?

Question 72

When a metal corrodes, what is happening chemically?

A) The metal atoms lose electrons.
B) The metal atoms gain electrons.
C) Electrons are not involved.
D) The metal is combining with nitrogen gas.
E) none of these

Question 73

In the balanced equation for the following reaction (in acidic solution) ClO₃^- + Fe²⁺ $\rightarrow$ Cl^- + Fe³⁺
The coefficient of Fe²⁺ is

A) 1
B) 6
C) 2
D) 8
E) 3

Question 74

In a galvanic cell that employs the reaction
Cu(s) + 2Ag⁺(aq) $\rightarrow$ Cu²⁺(aq) + 2Ag(s)
copper metal serves as the anode.

Question 75

In a galvanic cell that employs the reaction
Pb(s) + 2H₂SO₄(aq) + PbO₂(s) $\rightarrow$ 2PbSO₄(s) + 2H₂O(l)
lead metal serves as the cathode.

Question 76

In a lead storage battery, PbO₂ is found at the ______________.

A) cathode
B) anode
C) dry cell
D) galvanic cell
E) none of these

Question 77

Answer the following questions for a galvanic cell that employs the reaction
2Na(l) + S(l) $\rightarrow$ Na₂S(s)

-What element is oxidized?

Question 78

Aluminum resists corrosion in air because aluminum metal gains electrons rather than losing electrons.

Question 79

When the following reaction is balanced in acidic solution, what is the coefficient of water? Zn(s) + NO₃^-(aq) $\rightarrow$ Zn²⁺(aq) + NH₄⁺(aq)

A) 1
B) 2
C) 3
D) 4
E) none of these

Question 80

Answer the following questions for a galvanic cell that employs the reaction
2Na(l) + S(l) $\rightarrow$ Na₂S(s)

-What element serves as the anode?