Question 1

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

Accepted Answer

The substance that is the oxidizing agent is the substance that is being reduced. In this reaction, PbO and Pb are being reduced to PbSO4. Therefore, the oxidizing agent is PbO. Choice A, PbSO4, is one of the products of the reaction and therefore cannot be the oxidizing agent. Choice B, H2SO4, is not being reduced and therefore cannot be the oxidizing agent. Choice D, Pb, is being reduced and therefore cannot be the oxidizing agent. Choice E, H2SO4 and PbSO4, are products of the reaction and therefore cannot be the oxidizing agent.

Question 2

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

Accepted Answer

Zn(s) is the electrode where oxidation occurs (Zn → Zn2+ + 2e-), making it the anode. The cathode is where reduction occurs (Ni2+ + 2e- → Ni(s)), which in this case is Ni(s). The other options do not apply to Zn(s) in this reaction.

Question 3

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?

Accepted Answer

The half-reactions involved in this voltaic cell are: 
Cu(s) → Cu2+(aq) + 2e-
Ag+(aq) + e- → Ag(s)

The number of electrons lost in the oxidation half-reaction must be equal to the number of electrons gained in the reduction half-reaction. To achieve this, we need two silver ions (Ag+) to be reduced and one copper atom (Cu) to be oxidized:

Cu(s) + 2Ag+(aq) → Cu2+(aq) + 2Ag(s)

This equation is correctly balanced, but it is not one of the answer choices. However, choice C is the correct answer because it shows the same overall reaction, but with only one silver ion on each side of the equation. By multiplying each half-reaction by 2, we get:

2Cu(s) + 4Ag+(aq) → 2Cu2+(aq) + 4Ag(s)

Dividing both sides by 2 gives us the balanced equation:

Cu(s) + 2Ag+(aq) → Cu2+(aq) + 2Ag(s)

Question 4

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⁻? MnO₄⁻(aq)+ I⁻(aq)→ Mn²⁺(aq)+ I₂(aq)

Accepted Answer

The answer of The following reaction occurs in acid solution....

Question 5

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

Accepted Answer

In the given reaction, Zn is oxidized to ZnO and loses electrons, which is the process of oxidation. Therefore, the substance that is oxidized in this battery is Zn.

Question 6

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?

Accepted Answer

During the discharge of a lead storage battery, sulfate ions from sulfuric acid are consumed to form lead sulfate, thus decreasing the concentration of sulfuric acid in the solution.

Question 7

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

Accepted Answer

In a reduction-oxidation (redox) reaction, the substance that is reduced is the one that gains electrons. In this reaction, lead oxide (PbO) is reduced to lead (Pb) by gaining electrons. Therefore, the substance that is reduced in this battery is PbO₂.

Question 8

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

Accepted Answer

The answer of The figure shows a molecular-level representation of...

Question 9

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

Accepted Answer

Reduction involves a gain of electrons, and in this reaction, MnO₂ is reduced to Mn(OH)₂, indicating a decrease in the oxidation state of manganese.

Question 10

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?

Accepted Answer

The anode is where oxidation occurs, so the species being oxidized (Cu) should be on the left side of the equation, with the electrons as products. Choice B correctly shows Cu being oxidized to Cu(II) with the loss of 2 electrons.

Question 11

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

Accepted Answer

The answer of The figure shows a molecular-level representation of...

Question 12

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)→ MnO₄⁻(aq)+ Bi³⁺(aq)

Accepted Answer

The answer of The following reaction occurs in acid solution....

Question 13

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?

Accepted Answer

At the anode, oxidation occurs. The correct equation showing the oxidation of aluminum metal (Al) to aluminum ions (Al^3+) with the release of electrons is represented by choice A.

Question 14

Consider the half-reaction Cr³⁺(aq)→ Cr₂O₇²⁻(aq). When the equation is balanced in acid solution, the coefficient for water will be ________, and the number of electrons transferred will be ________.

Accepted Answer

First, we need to balance the equation by adding H+ ions and H2O molecules. The balanced equation in acid solution is: Cr^{3 + 14H+ + 8}(aq) → Cr₂O₇^{2− + 3H2O + 8}(aq) Next, we need to identify the species that undergoes a change in oxidation state. Here, we see that chromium (Cr) changes from +3 to +2, so it gains one electron. Each sulfur (S) atom in thiosulfate (S2O32-) changes from +2 to +4, so it loses two electrons. Therefore, in total, there are 8 electrons transferred (4 from each S2O32- ion). So the answer is (C) 7 water molecules and 6 electrons transferred. Note that the coefficient for water is one less than the total number of H+ ions added, which is 8 in this case.

Question 15

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?

Accepted Answer

To balance the oxidation half-reaction, we need to add 6 electrons to the left side to balance the charge of 3 aluminum atoms becoming Al3+ ions. This gives the equation: 2Al(s) → 2Al3+(aq) + 6e-. 
To balance the reduction half-reaction, we need to have 6 electrons added to the right side to balance 3 Ni2+ ions becoming 3 Ni atoms. This gives the equation: 3Ni2+(aq) + 6e- → 3Ni(s). 
Multiplying the oxidation reaction by 3 and the reduction reaction by 2 gives us the following overall balanced equation: 
2Al(s) + 3Ni2+(aq) → 2Al3+(aq) + 3Ni(s) 
When written with the sulfide ions in the electrolyte, this equation becomes: 
2Al(s) + 3NiS + 6H2O → 2Al(OH)3 + 3Ni(s) + 3H2S. 
Therefore, the correct balanced equation is C.

Question 16

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

Accepted Answer

The reducing agent is the substance that gives electrons and is oxidized. In this case, Pb is oxidized to PbSO4, which means it is losing electrons and is therefore the reducing agent.

Question 17

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

Accepted Answer

In the given reaction, zinc (Zn) is oxidized from its elemental state (Zn(s)) to form zinc oxide (ZnO(s)) and loses electrons in the process. Therefore, the substance that is oxidized in this battery is Zn.

Question 18

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

Accepted Answer

The reducing agent is the species that is oxidized (loses electrons) during the redox reaction. In this reaction, Zn(s) is the species that is oxidized to form ZnO(s), therefore, it is the reducing agent.

Question 19

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

Accepted Answer

During charging of a lead storage battery, PbO2 is formed at the anode through the oxidation of PbSO4, reversing the discharge reaction.

Question 20

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

Accepted Answer

The balanced equation requires two Fe³⁺ ions to balance the charge change from Sn²⁺ to Sn⁴⁺, resulting in two Fe²⁺ ions.

Quiz 14: Oxidation-Reduction Reactions

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

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

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?

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⁻? MnO₄⁻(aq) + I⁻(aq) → Mn²⁺(aq) + I₂(aq)

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

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

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

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

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?

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

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) → MnO₄⁻(aq) + Bi³⁺(aq)

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?

Consider the half-reaction Cr³⁺(aq) → Cr₂O₇²⁻(aq) . When the equation is balanced in acid solution, the coefficient for water will be , and the number of electrons transferred will be .

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

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

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

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

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

Quiz 14: Oxidation-Reduction Reactions

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

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

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?

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−? MnO4−(aq) + I−(aq) → Mn2+(aq) + I2(aq)

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

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

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

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

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?

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

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) → MnO4−(aq) + Bi3+(aq)

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?

Consider the half-reaction Cr3+(aq) → Cr2O72−(aq) . When the equation is balanced in acid solution, the coefficient for water will be ________, and the number of electrons transferred will be ________.

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

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

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

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

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