Deck 14: Oxidation-Reduction Reactions

Question 1

Which of the following reactions is not an oxidation-reduction reaction?

A)C(s) + CO₂(g) $\rightarrow$ CO₂(g)
B)CO(g) + Cl₂(g) $\rightarrow$ COCl₂(g)
C)2H₂O₂(l) $\rightarrow$ 2H₂O(l) + O₂(g)
D)CaCO₃(s) + 2HCl(aq) $\rightarrow$ CaCl₂(aq) + CO₂(g) + H₂O(l)
E)2HI(g) $\rightarrow$ H₂(g) + I₂(g)

Answer 1

CaCO₃(s) + 2HCl(aq) $\rightarrow$ CaCl₂(aq) + CO₂(g) + H₂O(l)

Question 2

In which of the following choices is the oxidation number incorrect?

A)Fe²⁺(aq); oxidation number = 2+
B)Cl^-(aq); oxidation number = 1-
C)H₂(s); oxidation number = 1+
D)Cu²⁺(aq); oxidation number = 2+
E)C(s); oxidation number = 0

Answer 2

H₂(s); oxidation number = 1+

Question 3

In which compound does bromine have an oxidation number of 3+?

A)Br₂O
B)BrO₃
C)Br₂O₃
D)BrO₂
E)Br₂O₅

Answer 3

Br₂O₃

Question 4

Consider the following reaction: Mg(s) + ZnSO₄(aq) $\rightarrow$ MgSO₄(aq) + Zn(s) Which of the following statements regarding this reaction is correct?

A)Magnesium is neither oxidized nor reduced.
B)The sulfate ion is reduced.
C)Zinc is the reducing agent.
D)Magnesium is the oxidizing agent.
E)Zinc gains two electrons.

Question 5

All of these statements concerning oxidation are correct except that

A)oxygen is necessary for oxidation to take place.
B)the oxidizing agent receives electrons from another species.
C)oxidation must accompany reduction.
D)the oxidizing agent increases the oxidation number of another element.
E)the oxidation of a metal produces positive ions.

Question 6

In which of the following choices is the oxidation number incorrect?

A)Al³⁺(aq); oxidation number = 3+
B)F^-(aq); oxidation number = 1-
C)Br₂(s); oxidation number = 0
D)Na⁺(aq); oxidation number = 1+
E)Cu(s); oxidation number = 2+

Question 7

In which compound does phosphorus have an oxidation number of 3-?

A)AlPO₄
B)PF₅
C)H₃PO₄
D)H₃PO₃
E)PH₃

Question 8

In which substance does chlorine have an oxidation number of 4+?

A)KClO₄
B)Cl₂
C)ClO₂
D)Cl₂O₇
E)NaCl

Question 9

In which compound does phosphorus have an oxidation number of 3+?

A)AlPO₄
B)PF₅
C)H₃PO₄
D)H₃PO₃
E)PH₃

Question 10

In which of the following choices is the oxidation number incorrect?

A)Fe³⁺(aq); oxidation number = 3+
B)I^-(aq); oxidation number = 1-
C)Cl₂(s); oxidation number = 1-
D)Cu⁺(aq); oxidation number = 1+
E)Ni(s); oxidation number = 0

Question 11

When a piece of copper wire is placed in a colorless solution of silver nitrate, the surface of the wire becomes coated with a shiny silvery material, and the copper begins to form aqueous copper(II) nitrate, which is blue.Which of the following statements regarding this reaction is correct?

A)The copper(II) is being oxidized.
B)The silver ion is being oxidized.
C)The nitrate ion is being reduced.
D)The solution will become more blue as the reaction progresses.
E)The reaction described is nonspontaneous.

Question 12

When a strip of zinc metal is placed in a blue aqueous solution of copper(II) sulfate, the surface of the zinc becomes coated with a reddish solid, and the zinc begins to dissolve to form aqueous zinc sulfate.Which of the following statements regarding this reaction is correct?

A)The copper(II) is being oxidized.
B)The zinc is being reduced.
C)The sulfate ion is being reduced.
D)The solution will lose its blue color as the reaction progresses.
E)The reaction described is nonspontaneous.

Question 13

Consider the following reaction: Mn(s) + CuSO₄(aq) $\rightarrow$ MnSO₄(aq) + Cu(s) Which of the following statements regarding this reaction is correct?

A)Manganese is neither oxidized nor reduced.
B)The sulfate ion is oxidized.
C)Copper is the reducing agent.
D)Manganese is the oxidizing agent.
E)Each copper gains two electrons.

Question 14

Which one of the following reactions is an example of an oxidation-reduction reaction?

A)BaO(s) + CO₂(g) $\rightarrow$ BaCO₃(s)
B)H₂(g) + F₂(g) $\rightarrow$ 2HF(g)
C)CaCO₃(s) $\rightarrow$ CaO(s) + CO₂(g)
D)HCl(aq) + NaOH(aq) $\rightarrow$ NaCl(aq) + H₂O(l)
E)Ba²⁺(aq) + SO₄^2-(aq) $\rightarrow$ BaSO₄(s)

Question 15

Consider the following reaction: Mg(s) + NiSO₄(aq) $\rightarrow$ MgSO₄(aq) + Ni(s) Which of the following statements regarding this reaction is correct?

A)Each magnesium atom gains two electrons.
B)The sulfate ion is reduced.
C)Nickel ion is the oxidizing agent.
D)Magnesium is reduced.
E)Each nickel ion loses two electrons.

Question 16

Which of the following statements regarding oxidation-reduction reactions is correct?

A)Oxidation-reduction reactions involve sharing electrons.
B)Oxidation can occur without reduction.
C)You can tell that a substance is oxidized if it loses electrons.
D)You can tell that a substance is reduced if its oxidation number increases.
E)None of these statements is correct.

Question 17

In which substance does chlorine have an oxidation number of 7+?

A)KClO₄
B)Cl₂
C)ClO₂
D)NaClO
E)NaCl

Question 18

In which of the following choices is the oxidation number incorrect?

A)Cr³⁺(aq); oxidation number = 3+
B)Cl^-(aq); oxidation number = 1-
C)F₂(g); oxidation number = 0
D)K⁺(aq); oxidation number = 1+
E)Ag(s); oxidation number = 1+

Question 19

What are the oxidation numbers of the atoms in the MnO₄- ion?

A)Mn = 0, O = 1-
B)Mn = 3+, O = 1-
C)Mn = 7+, O = 2-
D)Mn = 8+, O = 2-
E)Mn = 1-, O = 0

Question 20

The ion shown has a charge of 2-.What are the oxidation numbers of the atoms in the ion?

A)S = 0, O = 2-
B)S = 2-, O = 0
C)S = 8+, O = 2-
D)S = 6+, O = 2-
E)S = 4+, O = 1-

Question 21

Examine the following reaction: 5FeCl₂(aq) + KMnO₄(aq) + 8HCl(aq) $\rightarrow$ 5FeCl₃(aq) + MnCl₂(aq) + KCl(aq) + 4H₂O(l) Which element has undergone oxidation?

A)Fe
B)H
C)Cl
D)O
E)Mn

Question 22

Consider the reaction: N₂(g) + 3H₂(g) $\rightarrow$ 2NH₃(g) Which of the following statements is correct?

A)Nitrogen is oxidized.
B)Hydrogen is reduced.
C)Nitrogen is the reducing agent.
D)The reaction is not an oxidation-reduction reaction.
E)Hydrogen is the reducing agent.

Question 23

Consider the reaction: H₂O(l) + 3SO₃^2-(aq) + 2MnO₄^-(aq) $\rightarrow$ 3SO₄^2-(aq) + 2MnO₂(s) + 2OH^-(aq) Which species is oxidized?

A)H₂O
B)SO₃^2-
C)MnO^4-
D)SO₄^2-
E)MnO₂

Question 24

Which of the following sulfur species cannot be further reduced?

A)H₂SO₃
B)SO₄^2-
C)S₂O₃^2-
D)SO₃^2-
E)S^2-

Question 25

What is the oxidation number of boron in sodium tetraborate, Na₂B₄O₇?

A)+12
B)-3
C)+14
D)+3
E)+4

Question 26

Consider the reaction: Ba(NO₃)₂(aq) + Na₂SO₄(aq) $\rightarrow$ BaSO₄(s) + 2NaNO₃(aq) Which of the following statements is correct?

A)Barium is oxidized.
B)Sodium is reduced.
C)Nitrate ion is the reducing agent.
D)Sulfate ion is the oxidizing agent.
E)This reaction is not an oxidation-reduction reaction.

Question 27

Consider the following oxidation-reduction reaction: 2Fe³⁺(aq) + 2Hg(l) + 2Cl^-(aq) $\rightarrow$ 2Fe²⁺(aq) + Hg₂Cl₂(s) Which one of the following pairs correctly indicates the oxidizing agent and the reducing agent in this reaction? Oxidizing agent Reducing agent

A)Hg(l) Fe³⁺(aq)
B)Hg(l) Cl^-(aq)
C)Fe³⁺(aq) Cl^-(aq)
D)Fe³⁺(aq) Hg(l)
E)Cl^-(aq) Fe³⁺(aq)

Question 28

Consider the following reaction: 2Fe³⁺(aq) + 2Hg(l) + 2Cl^-(aq) $\rightarrow$ 2Fe²⁺(aq) + Hg₂Cl₂(s) In this reaction,

A)Fe³⁺(aq) is the reducing agent.
B)Fe³⁺(aq) loses electrons.
C)Hg(l) loses electrons.
D)Hg(l) is reduced.
E)Hg(l) is the oxidizing agent.

Question 29

Consider the reaction: CH₄(g) + 2O₂(g) $\rightarrow$ CO₂(g) + 2H₂O(g) Which of the following statements is correct?

A)Carbon is oxidized.
B)Oxygen is the reducing agent.
C)Oxygen is oxidized.
D)Carbon is the oxidizing agent.
E)The reaction is not an oxidation-reduction reaction.

Question 30

What are the oxidation numbers of the atoms in the AsO₄^3- ion?

A)As = 0, O = 1-
B)As = 1+, O = 1-
C)As = 3-, O = 0
D)As = 3+, O = 2-
E)As = 5+, O = 2-

Question 31

In which of the following does chlorine have an oxidation number of +3?

A)HCl
B)HOCl
C)HClO₂
D)HClO₃
E)HClO₄

Question 32

The change, Br₂ + H₂O $\rightarrow$ HOBr + HBr, is

A)oxidation only.
B)reduction only.
C)both oxidation and reduction.
D)neither oxidation nor reduction.
E)an acid-base reaction.

Question 33

What is the oxidation number of sulfur in S₂O₃^2-?

A)+6
B)-2
C)+4
D)+2
E)+3

Question 34

Consider the reaction: 2HgO(s) $\rightarrow$ 2Hg(l) + O₂(g) Which of the following statements is correct?

A)Mercury is reduced.
B)Oxygen is oxidized.
C)Mercury(II) ion is the oxidizing agent.
D)Oxide ion is the reducing agent.
E)All of these statements are correct.

Question 35

What are the oxidation numbers of the atoms in the Cr₂O₇^2- ion?

A)Cr = 1-, O = 0
B)Cr = 0, O = 2-
C)Cr = 6+, O = 2-
D)Cr = 7+, O = 2-
E)Cr = 3+, O = 1-

Question 36

What is the oxidation number of chlorine in sodium perchlorate, NaClO₄?

A)+8
B)-7
C)+16
D)+7
E)-8

Question 37

Consider the reaction: H₂O(l) + 3SO₃^2-(aq) + 2MnO₄^-(aq) $\rightarrow$ 3SO₄^2-(aq) + 2MnO₂(s) + 2OH^-(aq) Which species is the reducing agent?

A)H₂O
B)SO₃^2-
C)MnO_4-
D)SO₄^2-
E)MnO₂

Question 38

Consider the reaction: Ca(s) + 2H₂O(l) $\rightarrow$ Ca(OH)₂(aq) + H₂(g) Which of the following statements is correct?

A)Calcium is reduced.
B)Hydrogen is oxidized.
C)Oxygen is oxidized.
D)Oxygen is the reducing agent.
E)Calcium is oxidized.

Question 39

Consider the reaction: H₂O(l) + 3SO₃^2-(aq) + 2MnO₄^-(aq) $\rightarrow$ 3SO₄^2-(aq) + 2MnO₂(s) + 2OH^-(aq) Which species is reduced?

A)H₂O
B)SO₃^2-
C)MnO_4-
D)SO₄^2-
E)MnO₂

Question 40

Examine the following reaction: 5FeCl₂(aq) + KMnO₄(aq) + 8HCl(aq) - 5FeCl₃(aq) + MnCl₂(aq) + KCl(aq) + 4H₂O(l)
Which element has undergone reduction?

A)Fe
B)H
C)Cl
D)O
E)Mn

Question 41

Consider a voltaic cell that corresponds to the following reaction: Cu(s) + 2Ag⁺(aq) $\rightarrow$ Cu²⁺(aq) + Ag(s) Which of the following statements is correct?

A)Copper is the reducing agent.
B)The Cu²⁺ solution must be in the half-cell with the silver electrode.
C)No salt bridge is necessary, since the charge is 2+ on both sides of the equation.
D)The copper electrode is the cathode.
E)Four electrons will be transferred in this reaction per atom of copper that reacts.

Question 42

Consider a voltaic cell that corresponds to the following reaction: Mg(s) + Sn²⁺(aq) $\rightarrow$ Mg²⁺(aq) + Sn(s) Which of the following statements is correct?

A)Magnesium is the oxidizing agent.
B)The Sn²⁺ solution must be in the half-cell with the magnesium electrode.
C)No salt bridge is necessary, since the charge is 2+ on both sides of the equation.
D)The tin electrode is the cathode.
E)Four electrons will be transferred per atom of magnesium that reacts.

Question 43

For the following reaction, what is the oxidizing agent? 2Cl₂(g) + C(s) + 2H₂O(l) $\rightarrow$ CO₂(g) + 4HCl(aq)

A)Cl₂
B)C
C)H₂O
D)CO₂
E)HCl

Question 44

Consider the reaction: Zn(s) + H₂SO₄(aq) $\rightarrow$ ZnSO₄(aq) + H₂(g) Which species is the reducing agent, and how many electrons are transferred per atom of zinc that reacts?

A)Zn, 2 electrons
B)H⁺, 2 electrons
C)SO₄^2-, 4 electrons
D)Zn²⁺, 4 electrons
E)H₂, 2 electrons

Question 45

Consider the reaction: Sn²⁺(aq) + 2Fe³⁺(aq) $\rightarrow$ Sn⁴⁺(aq) + 2Fe²⁺(aq) Which species is reduced, and how many electrons are transferred per SN₂+ ion that reacts?

A)Sn²⁺, 2 electrons
B)Fe³⁺, 2 electrons
C)Sn⁴⁺, 4 electrons
D)Fe²⁺, 4 electrons
E)Fe²⁺, 2 electrons

Question 46

Given the following reaction in a voltaic cell: Cu(s) + 2Ag⁺(aq) $\rightarrow$ 2Ag(s) + Cu²⁺(aq) Which of the following statements is correct?

A)Cu(s) is the anode.
B)Oxidation occurs at the silver electrode.
C)There is no cathode for this cell.
D)Ag(s) is the anode.
E)One mole of electrons is transferred in the reaction as written.

Question 47

Consider the reaction: Cu(s) + 4HNO₃(aq) $\rightarrow$ Cu(NO₃)₂(aq) + 2NO₂(g) + 2OH^-(aq) Which species is oxidized?

A)OH^-
B)NO₂
C)Cu(NO₃)₂
D)HNO₃
E)Cu

Question 48

In a voltaic cell, the electron flow is always from

A)the salt bridge to the cathode.
B)the salt bridge to the anode.
C)the oxidizing agent through the salt bridge to the reducing agent.
D)the reducing agent through the salt bridge to the oxidizing agent.
E)the anode to the cathode.

Question 49

Consider a voltaic cell that corresponds to the following reaction: Zn(s) + Cu²⁺(aq) $\rightarrow$ Zn²⁺(aq) + Cu(s) If this reaction takes place in the electrochemical cell shown in the figure, which of the following statements is incorrect?

A)I is the zinc electrode, which is the anode.
B)II is the Cu2+ solution.
C)III is the salt bridge.
D)IV contains the substance that is being reduced.
E)V is the copper electrode, which is the cathode.

Question 50

Consider a voltaic cell that corresponds to the following reaction: Zn(s) + Cu²⁺(aq) $\rightarrow$ Zn²⁺(aq) + Cu(s) Which of the following statements is correct?

A)Zinc is the oxidizing agent.
B)The Cu²⁺ solution must be in the half-cell with the zinc electrode.
C)No salt bridge is necessary, since the charge is 2+ on both sides of the equation.
D)The zinc electrode is the cathode.
E)Two electrons will be transferred in this reaction per atom of zinc that reacts.

Question 51

Consider a voltaic cell that corresponds to the following reaction: Cu(s) + 2Ag⁺(aq) $\rightarrow$ Cu²⁺(aq) + Ag(s) If this reaction takes place in the electrochemical cell shown in the figure, which of the following statements is incorrect?

A)I is the copper electrode, which is the anode.
B)II is the Ag⁺ solution.
C)III is the salt bridge.
D)V contains the substance that is being reduced.
E)V is the silver electrode, which is the cathode.

Question 52

Consider the reaction: Cu(s) + 4HNO₃(aq) $\rightarrow$ Cu(NO₃)₂(aq) + 2NO₂(g) + 2OH^-(aq) Which species is the reducing agent?

A)OH^-
B)NO₂
C)Cu(NO₃)₂
D)HNO₃
E)Cu

Question 53

Consider the reaction: Cu(s) + 4HNO₃(aq) $\rightarrow$ Cu(NO₃)₂(aq) + 2NO₂(g) + 2OH^-(aq) Which species is the oxidizing agent?

A)OH^-
B)NO²
C)Cu(NO₃)₂
D)HNO₃
E)Cu

Question 54

Consider the reaction: Sn²⁺(aq) + 2Fe³⁺(aq) $\rightarrow$ Sn⁴⁺(aq) + 2Fe²⁺(aq) Which species is the oxidizing agent, and how many electrons are transferred per Sn²⁺ ion that reacts?

A)Sn²⁺, 2 electrons
B)Fe³⁺, 2 electrons
C)Sn⁴⁺, 4 electrons
D)Fe²⁺, 4 electrons
E)Fe²⁺, 2 electrons

Question 55

Consider the reaction: Zn(s) + H₂SO₄(aq) $\rightarrow$ ZnSO₄(aq) + H₂(g) Which species is oxidized, and how many electrons are transferred per atom of zinc that reacts?

A)Zn, 2 electrons
B)H⁺, 2 electrons
C)SO₄^2-, 4 electrons
D)Zn²⁺, 4 electrons
E)H₂, 2 electrons

Question 56

In a fuel cell that uses gaseous hydrogen and oxygen as reactants, which one of the following reactions is occurring at the anode?

A)2H₂O F $\rightarrow$ 2H₂ + O₂
B)H₂ $\rightarrow$ 2H⁺ + 2e^-
C)2H⁺ + 2e^- $\rightarrow$ H₂
D)O₂ + 4e^- $\rightarrow$ 2O^2-
E)2O^2- $\rightarrow$ O₂ + 4e^-

Question 57

Consider the reaction: Zn(s) + H₂SO₄(aq) $\rightarrow$ ZnSO₄(aq) + H₂(g) Which species is reduced, and how many electrons are transferred per atom of zinc that reacts?

A)Zn, 2 electrons
B)H⁺, 2 electrons
C)SO₄^2-, 4 electrons
D)Zn²⁺, 4 electrons
E)H₂, 2 electrons

Question 58

Consider a voltaic cell that corresponds to the following reaction: Fe(s) + Ni²⁺(aq) $\rightarrow$ Fe²⁺(aq) + Ni(s) Which of the following statements is correct?

A)Iron is the oxidizing agent.
B)The Ni²⁺ solution must be in the half-cell with the iron electrode.
C)No salt bridge is necessary, since the charge is 2+ on both sides of the equation.
D)The nickel electrode is the cathode.
E)Four electrons will be transferred per atom of iron that reacts.

Question 59

Consider a voltaic cell that corresponds to the following reaction: Mg(s) + Sn²⁺(aq) $\rightarrow$ Mg²⁺(aq) + Sn(s) If this reaction takes place in the electrochemical cell shown in the figure, which of the following statements is incorrect?

A)I is the magnesium electrode, which is the anode.
B)II is the Mg²⁺ solution.
C)III is the salt bridge.
D)IV contains the substance that is being oxidized.
E)V is the tin electrode, which is the cathode.

Question 60

Consider the reaction: Sn²⁺(aq) + 2Fe³⁺(aq) $\rightarrow$ Sn⁴⁺(aq) + 2Fe²⁺(aq) Which species is oxidized, and how many electrons are transferred per SN₂+ ion that reacts?

A)Sn²⁺, 2 electrons
B)Fe³⁺, 2 electrons
C)Sn⁴⁺, 4 electrons
D)Fe²⁺, 4 electrons
E)Fe²⁺, 2 electrons

Question 61

A voltaic cell is prepared in which copper metal is oxidized to Cu(II), and silver ion is reduced to silver metal.Which of the following represents the equation for the reaction that occurs at the anode?

A)Cu(s) - 2e^- $\rightarrow$ Cu²⁺(aq)
B)Cu(s) $\rightarrow$ Cu²⁺(aq) + 2e^-
C)2Cu(s) $\rightarrow$ 2Cu²⁺(aq) + e^-
D)Ag⁺(aq) + e^- $\rightarrow$ Ag(s)
E)Ag(s) $\rightarrow$ Ag⁺(aq) + e^-

Question 62

A mercury button battery that is used in watches and calculators is powered by the following reaction: Zn(s) + HgO(s) $\rightarrow$ ZnO(s) + Hg(s) The substance that is oxidized in this battery is:

A)HgO
B)Hg
C)ZnO
D)Zn

Question 63

The reaction that occurs in an alkaline battery is as follows: Zn(s) + MnO₂(s) + H₂O(l) $\rightarrow$ ZnO(s) + Mn(OH)₂(s) The substance that is oxidized in this battery is:

A)Zn
B)ZnO
C)MnO₂
D)H₂O
E)Mn(OH)₂

Question 64

The reaction that occurs in an alkaline battery is as follows: Zn(s) + MnO₂(s) + H₂O(l) $\rightarrow$ ZnO(s) + Mn(OH)₂(s) The substance that is reduced in this battery is:

A)Zn
B)ZnO
C)MnO₂
D)H₂O
E)Mn(OH)₂

Question 65

The following reaction occurs in acid solution.When the equation is properly balanced with the smallest whole-number coefficients, what is the coefficient of Bi³⁺? Mn²⁺(aq) + BiO₃^-(aq) $\rightarrow$ MnO₄^-(aq) + Bi³⁺(aq)

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

Question 66

A voltaic cell is prepared in which copper metal is oxidized to Cu(II), and silver ion is reduced to silver metal.Which of the following represents the correctly balanced equation for this reaction?

A)Cu(s) + Ag⁺(aq) $\rightarrow$ Cu²⁺(aq) + Ag(s)
B)2Cu(s) + Ag⁺(aq) $\rightarrow$ 2Cu²⁺(aq) + Ag(s)
C)Cu(s) + 2Ag⁺(aq) $\rightarrow$ Cu²⁺(aq) + 2Ag(s)
D)3Cu(s) + 2Ag⁺(aq) $\rightarrow$ 3Cu²⁺(aq) + 2Ag(s)
E)2Cu(s) + 3Ag+(aq) $\rightarrow$ 2Cu²⁺(aq) + 3Ag(s)

Question 67

A voltaic cell is prepared in which aluminum metal is oxidized to Al³⁺, and nickel(II) is reduced to nickel metal.Which of the following represents the equation for the reaction that occurs at the anode?

A)Al(s) $\rightarrow$ Al³⁺(aq) + 3e^-
B)Ni²⁺(aq) + 2e^- $\rightarrow$ Ni(s)
C)Ni(s) $\rightarrow$ Ni²⁺(aq) + 2e^-
D)Al³⁺(aq) + 3e^- $\rightarrow$ Al(s)
E)2Al³⁺(aq) + 3e^- $\rightarrow$ 2Al(s)

Question 68

The following reaction occurs in a lead storage battery: PbO₂(s) + Pb(s) + H₂SO₄(aq) ⇌ 2PbSO₄(s) + 2H₂O(l) Which statement is true?

A)The concentration of H₂SO4 increases as the battery discharges.
B)Pb is formed at the anode during charging.
C)PbO₂ is formed at the anode during charging.
D)The mass of Pb decreases during charging.
E)The mass of PbSO₄ remains constant during charging and discharging.

Question 69

The following reaction occurs in acid solution.When the equation is properly balanced with the smallest whole-number coefficients, what is the coefficient of MnO₄- $\rightarrow$ MnO₄-(aq) + I^-(aq) $\rightarrow$ Mn²⁺(aq) + I²(aq)

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

Question 70

Given the following reaction in a voltaic cell: Zn(s) + Ni²⁺(aq) $\rightarrow$ Ni(s) + Zn²⁺(aq) In this cell, Zn(s) is called the

A)anode.
B)oxidizing agent.
C)salt bridge.
D)electrolyte.
E)cathode.

Question 71

Consider the skeletal equation: Sn²⁺(aq) + Fe³⁺(aq) $\rightarrow$ Sn⁴⁺(aq) + Fe²⁺(aq) When balanced, the equation will be:

A)Sn²⁺(aq) + Fe³⁺(aq) $\rightarrow$ Sn⁴⁺(aq) + Fe²⁺(aq)
B)2Sn²⁺(aq) + Fe³⁺(aq) $\rightarrow$ Sn⁴⁺(aq) + Fe²⁺(aq)
C)2Sn²⁺(aq) + Fe³⁺(aq) $\rightarrow$ 2Sn⁴⁺(aq) + Fe²⁺(aq)
D)Sn²⁺(aq) + 2Fe³⁺(aq) $\rightarrow$ Sn⁴⁺(aq) + 2Fe²⁺(aq)
E)4Sn²⁺(aq) + Fe³⁺(aq) $\rightarrow$ 2Sn⁴⁺(aq) + Fe²⁺(aq)

Question 72

The figure shows a molecular-level representation of the following voltaic cell: Mg(s) + Sn²⁺(aq) $\rightarrow$ Mg²⁺(aq) + Sn(s) When drawing the "after" representation one would note that:

A)the tin electrode will be smaller.
B)the magnesium electrode will be larger.
C)the number of Mg²⁺ ions in solution will remain constant.
D)deposits will form in the salt bridge.
E)the number of Sn²⁺ ions in solution will decrease.

Question 73

A lead-acid battery that is used in cars and trucks is powered by the reaction: PbO₂(s) + Pb(s) + 2H₂SO₄(aq) $\rightarrow$ 2PbSO₄(s) + H₂O(l) The substance that is the oxidizing agent in this battery is:

A)PbSO₄
B)H₂O
C)PbO₂
D)Pb
E)H₂SO₄

Question 74

The figure shows a molecular-level representation of the following voltaic cell: Fe(s) + Ni²⁺(aq) $\rightarrow$ Fe²⁺(aq) + Ni(s) When drawing the "after" representation one would note that:

A)the nickel electrode will be smaller.
B)the iron electrode will be larger.
C)the number of Ni²⁺ ions in solution will decrease.
D)deposits will form in the salt bridge.
E)the number of Fe²⁺ ions in solution will remain constant.

Question 75

Consider the half-reaction Cr³⁺(aq) $\rightarrow$ Cr₂O₇^2-(aq).When the equation is balanced in acid solution, the coefficient for water will be__________, and the number of electrons transferred will be __________.

A)3, 3
B)6, 6
C)7, 6
D)5, 4
E)3, 6

Question 76

The following reaction occurs in a lead storage battery: PbO₂(s) + Pb(s) + H₂SO₄(aq) ⇌ 2PbSO₄(s) + 2H₂O(l) What happens to the sulfuric acid in a lead storage battery when the battery is being discharged?

A)Sulfate ions are consumed and their concentration decreases.
B)Protons are released so the pH drops.
C)The solution gets increasingly more viscous due to an increase in sulfuric acid concentration.
D)Its concentration increases.
E)All of these are correct.

Question 77

A voltaic cell is prepared in which aluminum metal is oxidized to Al³⁺, and nickel(II) is reduced to nickel metal.Which of the following represents the correctly balanced equation for this reaction?

A)Al(s) + Ni²⁺(aq) $\rightarrow$ Al³⁺(aq) + Ni(s)
B)Al(s) + 2Ni²⁺(aq) $\rightarrow$ Al³⁺(aq) + 2Ni(s)
C)2Al(s) + 3Ni²⁺(aq) $\rightarrow$ 2Al³⁺(aq) + 3Ni(s)
D)Al³⁺(aq) + 2Ni(s) $\rightarrow$ Al(s) + 2Ni²⁺(aq)
E)2Al³⁺(aq) + 3Ni(s) $\rightarrow$ 2Al(s) + 3Ni²⁺(aq)

Question 78

A lead-acid battery that is used in cars and trucks is powered by the reaction: PbO₂(s) + Pb(s) + 2H₂SO₄(aq) $\rightarrow$ 2PbSO₄(s) + H₂O(l) The substance that is the reducing agent in this battery is:

A)PbSO₄
B)H₂O
C)PbO₂
D)Pb
E)H₂SO₄

Question 79

A lead-acid battery that is used in cars and trucks is powered by the reaction: PbO₂(s) + Pb(s) + 2H₂SO₄(aq) $\rightarrow$ 2PbSO₄(s) + H₂O(l) The substance that is reduced in this battery is:

A)PbSO₄
B)H₂O
C)PbO₂
D)Pb
E)H₂SO₄

Question 80

The reaction that occurs in an alkaline battery is as follows: Zn(s) + MnO₂(s) + H₂O(l) $\rightarrow$ ZnO(s) + Mn(OH)₂(s) The substance that is the reducing agent in this battery is:

A)Zn
B)ZnO
C)MnO₂
D)H₂O
E)Mn(OH)₂