Question 1

Which of the following is the overall reaction of the Leclanche dry cell?

Accepted Answer

A)  Zn(s) + 2HgO(s)→Hg(l)+ZnO(s) 
B)  2MnO2(s) + 2NH4Cl(aq) + Zn(s) → Mn2O3(s) + Zn(NH3)2Cl2(s) + H2O(l) 
C)  Zn(s) + 2Ag2O(s)→2Ag(s)+ZnO(s) 
D)  Cd(s)+2NiO(OH)(s)+2H2O(l)→Cd(OH)2(s)+2Ni(OH)2(s) 
E)  Pb(s) + PbO2(s)+2HSO4−(aq)+2H+(aq)→2PbSO4(s)+2H2O(l) 
A)  Zn(s) + 2HgO(s)→Hg(l)+ZnO(s) 
B)  2MnO2(s) + 2NH4Cl(aq) + Zn(s) → Mn2O3(s) + Zn(NH3)2Cl2(s) + H2O(l) 
C)  Zn(s) + 2Ag2O(s)→2Ag(s)+ZnO(s) 
D)  Cd(s)+2NiO(OH)(s)+2H2O(l)→Cd(OH)2(s)+2Ni(OH)2(s) 
E)  Pb(s) + PbO2(s)+2HSO4−(aq)+2H+(aq)→2PbSO4(s)+2H2O(l) B

Question 2

Compare and contrast galvanic cells and electrolytic cells.

Accepted Answer

A galvanic cell uses the energy released during a spontaneous redox reaction (ΔG < 0) to generate electricity. This type of electrochemical cell is often called a voltaic cell. In contrast, an electrolytic cell consumes electrical energy from an external source, using it to cause a nonspontaneous redox reaction to occur (ΔG > 0).
Both types contain two electrodes, which are solid metals connected to an external circuit that provides an electrical connection between the two parts of the system. The oxidation half-reaction occurs at one electrode (the anode), and the reduction half-reaction occurs at the other (the cathode). The electrodes are also connected by an electrolyte, an ionic substance or solution that allows ions to transfer between the electrode compartments, thereby maintaining the system's electrical neutrality.

Question 3

All reactants that lie above the standard hydrogen electrode in the table are stronger reductants than H+.

Accepted Answer

A) True 
 B)False  False

Question 4

_____ is the fundamental SI unit of electric current.

Accepted Answer

The answer of _____ is the fundamental SI unit of...

Question 5

Which of the following is the overall reaction for the formation of rust?

Accepted Answer

A)  2MnO2(s) + 2NH4Cl(aq) + Zn(s) → Mn2O3(s) + Zn(NH3)2Cl2(s) + H2O(l) 
B)  Cd(s)+2NiO(OH)(s)+2H2O(l)→Cd(OH)2(s)+2Ni(OH)2(s) 
C)  4Fe2+(aq) + O2(g) + (2 + 4x)H2O → 2Fe2O3·xH2O + 4H+(aq) 
D)  Zn(s) + 2MnO2(s)→ZnO(s)+Mn2O3(s) 
E)  2Zn(s) + O2(g)+4H+(aq)→2Zn2+(aq)+2H2O(l) 
A)  2MnO2(s) + 2NH4Cl(aq) + Zn(s) → Mn2O3(s) + Zn(NH3)2Cl2(s) + H2O(l) 
B)  Cd(s)+2NiO(OH)(s)+2H2O(l)→Cd(OH)2(s)+2Ni(OH)2(s) 
C)  4Fe2+(aq) + O2(g) + (2 + 4x)H2O → 2Fe2O3·xH2O + 4H+(aq) 
D)  Zn(s) + 2MnO2(s)→ZnO(s)+Mn2O3(s) 
E)  2Zn(s) + O2(g)+4H+(aq)→2Zn2+(aq)+2H2O(l)

Question 6

Which of the following elements is most likely to be the strongest reductant in aqueous solution?

Accepted Answer

A)  Li+ 
B)  Al3+ 
C)  Zn2+ 
D)  Sn4+ 
E)  Cu2+ 
A)  Li+ 
B)  Al3+ 
C)  Zn2+ 
D)  Sn4+ 
E)  Cu2+

Question 7

Explain the method used to protect iron from corrosion.

Accepted Answer

In the approach, called cathodic protect

Question 8

An electrochemical cell in which the anode and cathode compartments are identical except for the concentration of a reactant is called a(n) _____.

Accepted Answer

The answer of An electrochemical cell in which the anode...

Question 9

A galvanic cell consists of two beakers. One beaker contains a strip of lead immersed in aqueous sulfuric acid, and the other contains a platinum electrode immersed in aqueous nitric acid. The two solutions are connected by a salt bridge, and the electrodes are connected by a wire. Current begins to flow, and bubbles of a gas appear at the platinum electrode. The spontaneous redox reaction that occurs is described by the following balanced chemical equation: $$3 \mathrm {~Pb} ( \mathrm {~s} ) + 2 \mathrm { NO } _ { 3 } ^ { - } ( \mathrm { aq } ) + 8 \mathrm { H } ^ { + } ( \mathrm { aq } ) \rightarrow 3 \mathrm {~Pb} ^ { 2 + } ( \mathrm { aq } ) + 2 \mathrm { NO } ( \mathrm { g } ) + 4 \mathrm { H } _ { 2 } \mathrm { O } ( \mathrm { l } )$$ Which of the following is the oxidation half-reaction that occurs in the anode?

Accepted Answer

A)  $$\mathrm { Pb } ( \mathrm { s } ) \rightarrow \mathrm { Pb } ^ { 2 + } ( \mathrm { aq } ) + 2 \mathrm { e } ^ { - }$$ 
B)  $\mathrm { NO } _ { 3 } ^ { - } ( \mathrm { aq } ) + 3 \mathrm { e } ^ { - } \rightarrow \mathrm { NO } ( \mathrm { g } )$ 
C)  $\mathrm { NO } _ { 3 } ^ { - } ( \mathrm { aq } ) + 4 \mathrm { H } ^ { + } ( \mathrm { aq } ) + 3 \mathrm { e } ^ { - } \rightarrow \mathrm { NO } ( \mathrm { g } ) + 2 \mathrm { H } _ { 2 } \mathrm { O } ( \mathrm { l } )$ 
D)  $\mathrm { Pb } ^ { 2 + } ( \mathrm { aq } ) + \mathrm { H } _ { 2 } \mathrm { O } ( \mathrm { l } ) \rightarrow \mathrm { PbO } ( \mathrm { s } ) + 2 \mathrm { H } ^ { + } ( \mathrm { aq } ) + 2 \mathrm { e } ^ { - }$ 
E)  $3 \mathrm {~Pb} ( \mathrm {~s} ) + 2 \mathrm { NO } _ { 3 } ^ { - } ( \mathrm { aq } ) \rightarrow 3 \mathrm {~Pb} ^ { 2 + } ( \mathrm { aq } ) + 2 \mathrm { NO } ( \mathrm { g } ) + 3 \mathrm { e } ^ { - }$ 
A)  $$\mathrm { Pb } ( \mathrm { s } ) \rightarrow \mathrm { Pb } ^ { 2 + } ( \mathrm { aq } ) + 2 \mathrm { e } ^ { - }$$ 
B)  $\mathrm { NO } _ { 3 } ^ { - } ( \mathrm { aq } ) + 3 \mathrm { e } ^ { - } \rightarrow \mathrm { NO } ( \mathrm { g } )$ 
C)  $\mathrm { NO } _ { 3 } ^ { - } ( \mathrm { aq } ) + 4 \mathrm { H } ^ { + } ( \mathrm { aq } ) + 3 \mathrm { e } ^ { - } \rightarrow \mathrm { NO } ( \mathrm { g } ) + 2 \mathrm { H } _ { 2 } \mathrm { O } ( \mathrm { l } )$ 
D)  $\mathrm { Pb } ^ { 2 + } ( \mathrm { aq } ) + \mathrm { H } _ { 2 } \mathrm { O } ( \mathrm { l } ) \rightarrow \mathrm { PbO } ( \mathrm { s } ) + 2 \mathrm { H } ^ { + } ( \mathrm { aq } ) + 2 \mathrm { e } ^ { - }$ 
E)  $3 \mathrm {~Pb} ( \mathrm {~s} ) + 2 \mathrm { NO } _ { 3 } ^ { - } ( \mathrm { aq } ) \rightarrow 3 \mathrm {~Pb} ^ { 2 + } ( \mathrm { aq } ) + 2 \mathrm { NO } ( \mathrm { g } ) + 3 \mathrm { e } ^ { - }$

Question 10

If $E _ { \text {cell } }$ = - 0.76 V, what is the value of the solubility product of the salt?

Accepted Answer

A)  2.7×10-12 
B)  1.4×10-13 
C)  3.9×10-13 
D)  5.6×10-12 
E)  7.2×10-13 
A)  2.7×10-12 
B)  1.4×10-13 
C)  3.9×10-13 
D)  5.6×10-12 
E)  7.2×10-13

Question 11

_____ is the study of the relationship between electricity and chemical reactions.

Accepted Answer

The answer of _____ is the study of the relationship...

Question 12

The _____ is a battery consisting of an electrolyte that is an acidic water-based paste containing MnO2, NH4Cl, ZnCl2, graphite, and starch.

Accepted Answer

Question 13

If the reaction 2Ce4+(aq) + 2Cl?(aq) ? 2Ce3+(aq) + Cl2(g) is likely to occur spontaneously under normal conditions, what is the $E _ { \text {cell } } ^ { \circ }$ for the reaction?(Use data in the Table 19.2)

Accepted Answer

A)  -0.36V 
B)  1.72 V 
C)  1.36 V 
D)  3.08 V 
E)  0.36 V 
A)  -0.36V 
B)  1.72 V 
C)  1.36 V 
D)  3.08 V 
E)  0.36 V

Question 14

_____ is the process in which a layer of a second metal is deposited on the metal electrode that acts as the cathode during electrolysis.

Accepted Answer

The answer of _____ is the process in which a...

Question 15

For the thermodynamically nonspontaneous decomposition of water into H2 at the cathode and O2 at the anode, what is $E _ { \text {cell } }$ for the overall reaction? Given: $P _ { \mathrm { O } _ { 2 } } = P _ { \mathrm { H } _ { 2 } }$ = 1 atm.

Accepted Answer

A)  -2.46 V 
B)  3.69 V 
C)  1.23 V 
D)  2.46 V 
E)  -1.23 V 
A)  -2.46 V 
B)  3.69 V 
C)  1.23 V 
D)  2.46 V 
E)  -1.23 V

Question 16

A galvanic cell consists of two beakers. One beaker contains a strip of lead immersed in aqueous sulfuric acid, and the other contains a platinum electrode immersed in aqueous nitric acid. The two solutions are connected by a salt bridge, and the electrodes are connected by a wire. Current begins to flow, and bubbles of a gas appear at the platinum electrode. The spontaneous redox reaction that occurs is described by the following balanced chemical equation: $$3 \mathrm {~Pb} ( \mathrm {~s} ) + 2 \mathrm { NO } _ { 3 } ^ { - } ( \mathrm { aq } ) + 8 \mathrm { H } ^ { + } ( \mathrm { aq } ) \rightarrow 3 \mathrm {~Pb} ^ { 2 + } ( \mathrm { aq } ) + 2 \mathrm { NO } ( \mathrm { g } ) + 4 \mathrm { H } _ { 2 } \mathrm { O } ( \mathrm { l } )$$ Which of the following is the cell diagram for the galvanic cell?

Accepted Answer

A)  $\mathrm{Pt}(\mathrm{s})\left|\mathrm{Pb}^{2+}(\mathrm{aq}) \mathrm{PH}\mathrm{NO}_{3}(\mathrm{aq})\right| \mathrm{NO}(\mathrm{g}) \mid \mathrm{Pb}(\mathrm{s})$ 
B)  $\mathrm { Pb } ( \mathrm { s } ) \left| \mathrm { Pb } ^ { 2 + } ( \mathrm { aq } ) \mathrm { PNO } ( \mathrm { g } ) \right| \mathrm { Pt } ( \mathrm { s } )$ 
C)  $\mathrm { Pt } ( \mathrm { s } ) \mid \mathrm { Pb } ^ { 2 + } \text { (aq) } \mathrm { PHNO } _ { 3 } ( \mathrm { aq } ) \mid \mathrm { Pb } ( \mathrm { s } )$ 
D)  $\mathrm { Pb } ( \mathrm { s } ) \left| \mathrm { Pb } ^ { 2 + } ( \mathrm { aq } ) \right| \mathrm { NO } ( \mathrm { g } ) \mathrm { PHNO } _ { 3 } ( \mathrm { aq } ) \mid \mathrm { Pt } ( \mathrm { s } )$ 
E)  $\mathrm { Pb } ( \mathrm { s } ) \left| \mathrm { Pb } ^ { 2 + } ( \mathrm { aq } ) \mathrm { PHNO } _ { 3 } ( \mathrm { aq } ) \right| \mathrm { NO } ( \mathrm { g } ) \mid \mathrm { Pt } ( \mathrm { s } )$ 
A)  $\mathrm{Pt}(\mathrm{s})\left|\mathrm{Pb}^{2+}(\mathrm{aq}) \mathrm{PH}\mathrm{NO}_{3}(\mathrm{aq})\right| \mathrm{NO}(\mathrm{g}) \mid \mathrm{Pb}(\mathrm{s})$ 
B)  $\mathrm { Pb } ( \mathrm { s } ) \left| \mathrm { Pb } ^ { 2 + } ( \mathrm { aq } ) \mathrm { PNO } ( \mathrm { g } ) \right| \mathrm { Pt } ( \mathrm { s } )$ 
C)  $\mathrm { Pt } ( \mathrm { s } ) \mid \mathrm { Pb } ^ { 2 + } \text { (aq) } \mathrm { PHNO } _ { 3 } ( \mathrm { aq } ) \mid \mathrm { Pb } ( \mathrm { s } )$ 
D)  $\mathrm { Pb } ( \mathrm { s } ) \left| \mathrm { Pb } ^ { 2 + } ( \mathrm { aq } ) \right| \mathrm { NO } ( \mathrm { g } ) \mathrm { PHNO } _ { 3 } ( \mathrm { aq } ) \mid \mathrm { Pt } ( \mathrm { s } )$ 
E)  $\mathrm { Pb } ( \mathrm { s } ) \left| \mathrm { Pb } ^ { 2 + } ( \mathrm { aq } ) \mathrm { PHNO } _ { 3 } ( \mathrm { aq } ) \right| \mathrm { NO } ( \mathrm { g } ) \mid \mathrm { Pt } ( \mathrm { s } )$

Question 17

Any species on the left side of a half-reaction will spontaneously oxidize any species on the right side of another half-reaction that lies above it in the table.

Accepted Answer

A) True 
 B)False

Question 18

_____ is the additional voltage required to overcome barriers such as the large activation energy for the formation of a gas at a metal surface.

Accepted Answer

The answer of _____ is the additional voltage required to...

Question 19

_____ are electrodes that contain a more reactive metal that is attached to a metal object to inhibit that object's corrosion.

Accepted Answer

Sacrificia

Question 20

Which of the following is the half-reaction that occurs at the cathode of the Leclanche dry cell?

Accepted Answer

A)  PbO2 (s)+ $\mathrm { HSO } _ { 4 } ^ { - }$ (aq)+3H+(aq)+2e- ?PbSO4(s)+2H2O(l) 
B)  2NiO(OH)(s) + 2H2O(l) + 2e? ? 2Ni(OH)2(s) + 2OH?(aq) 
C)  HgO(s) + H2O(l) + 2e? ? Hg(l) + 2OH?(aq) 
D)  2MnO2(s) + 2NH4+(aq) + 2e? ? Mn2O3(s) + 2NH3(aq) + H2O(l) 
E)  Ag2O(s) + H2O(l) + 2e? ? 2Ag(s) + 2OH?(aq) 
A)  PbO2 (s)+ $\mathrm { HSO } _ { 4 } ^ { - }$ (aq)+3H+(aq)+2e- ?PbSO4(s)+2H2O(l) 
B)  2NiO(OH)(s) + 2H2O(l) + 2e? ? 2Ni(OH)2(s) + 2OH?(aq) 
C)  HgO(s) + H2O(l) + 2e? ? Hg(l) + 2OH?(aq) 
D)  2MnO2(s) + 2NH4+(aq) + 2e? ? Mn2O3(s) + 2NH3(aq) + H2O(l) 
E)  Ag2O(s) + H2O(l) + 2e? ? 2Ag(s) + 2OH?(aq)

Exam 19: Electrochemistry

Which of the following is the overall reaction of the Leclanche dry cell?

Compare and contrast galvanic cells and electrolytic cells.

All reactants that lie above the standard hydrogen electrode in the table are stronger reductants than H+.

_____ is the fundamental SI unit of electric current.

Which of the following is the overall reaction for the formation of rust?

Which of the following elements is most likely to be the strongest reductant in aqueous solution?

Explain the method used to protect iron from corrosion.

An electrochemical cell in which the anode and cathode compartments are identical except for the concentration of a reactant is called a(n) _____.

If Ecell E _ { \text {cell } }Ecell ​ = - 0.76 V, what is the value of the solubility product of the salt?

_____ is the study of the relationship between electricity and chemical reactions.

The _____ is a battery consisting of an electrolyte that is an acidic water-based paste containing MnO2, NH4Cl, ZnCl2, graphite, and starch.

If the reaction 2Ce4+(aq) + 2Cl?(aq) ? 2Ce3+(aq) + Cl2(g) is likely to occur spontaneously under normal conditions, what is the Ecell ∘E _ { \text {cell } } ^ { \circ }Ecell ∘​ for the reaction?(Use data in the Table 19.2)

_____ is the process in which a layer of a second metal is deposited on the metal electrode that acts as the cathode during electrolysis.

For the thermodynamically nonspontaneous decomposition of water into H2 at the cathode and O2 at the anode, what is Ecell E _ { \text {cell } }Ecell ​ for the overall reaction? Given: PO2=PH2P _ { \mathrm { O } _ { 2 } } = P _ { \mathrm { H } _ { 2 } }PO2​​=PH2​​ = 1 atm.

Any species on the left side of a half-reaction will spontaneously oxidize any species on the right side of another half-reaction that lies above it in the table.

_____ is the additional voltage required to overcome barriers such as the large activation energy for the formation of a gas at a metal surface.

_____ are electrodes that contain a more reactive metal that is attached to a metal object to inhibit that object's corrosion.

Which of the following is the half-reaction that occurs at the cathode of the Leclanche dry cell?

Introduction to Chemistry

Molecules, Ions, and Chemical Formulas

Chemical Reactions

Reactions in Aqueous Solution

Energy Changes in Chemical Reactions

The Structure of Atoms

The Periodic Table and Periodic Trends

Ionic Versus Covalent Bonding

Molecular Geometry and Covalent Bonding Models

Gases

Liquids

Solids

Solutions

Chemical Kinetics

Chemical Equilibrium

Aqueous Acidbase Equilibriums

Solubility and Complexation Equilibriums

Chemical Thermodynamics

Nuclear Chemistry

Periodic Trends and the S-Block Elements

The P-Block Elements

The D-Block Elements

Organic Compounds

Filters

All reactants that lie above the standard hydrogen electrode in the table are stronger reductants than H⁺.

If $E _ { \text {cell } }$ = - 0.76 V, what is the value of the solubility product of the salt?

The _____ is a battery consisting of an electrolyte that is an acidic water-based paste containing MnO₂, NH₄Cl, ZnCl₂, graphite, and starch.

If the reaction 2Ce⁴⁺(aq) + 2Cl^?(aq) ? 2Ce³⁺(aq) + Cl₂(g) is likely to occur spontaneously under normal conditions, what is the $E _ { \text {cell } } ^ { \circ }$ for the reaction?(Use data in the Table 19.2)

For the thermodynamically nonspontaneous decomposition of water into H₂ at the cathode and O₂ at the anode, what is $E _ { \text {cell } }$ for the overall reaction? Given: $P _ { \mathrm { O } _ { 2 } } = P _ { \mathrm { H } _ { 2 } }$ = 1 atm.