Deck 20: Electrochemistry

Question 1

Balance the following redox reaction if it occurs in H₂SO₄.What are the coefficients in front of H₂O and Cr₂(SO₄)₃ in the balanced reaction?
C₃H₈O₂(aq)+ K₂Cr₂O₇(aq)→ C₃H₄O₄(aq)+ Cr₂(SO₄)₃(aq)

A) H₂O = 1, Cr₂(SO₄)₃ = 5
B) H₂O = 5, Cr₂(SO₄)₃ = 2
C) H₂O = 11, Cr₂(SO₄)₃ = 4
D) H₂O = 22, Cr₂(SO₄)₃ = 4
E) H₂O = 8, Cr₂(SO₄)₃ = 2

Answer 1

H₂O = 22, Cr₂(SO₄)₃ = 4

Question 2

Balance the following reaction in KOH.What are the coefficients in front of C₃H₈O₂ and KMnO₄ in the balanced reaction?
C₃H₈O₂(aq)+ KMnO₄(aq)→ C₃H₂O₄K₂(aq)+ MnO₂(aq)

A) C₃H₈O₂ = 3, KMnO₄ = 8
B) C₃H₈O₂ = 3, KMnO₄ = 4
C) C₃H₈O₂ = 8, KMnO₄ = 3
D) C₃H₈O₂ = 2, KMnO₄ = 4
E) C₃H₈O₂ = 3, KMnO₄ = 2

Answer 2

C₃H₈O₂ = 3, KMnO₄ = 8

Question 3

What element is being oxidized in the following redox reaction?
C₃H₈O₂(aq)+ KMnO₄(aq)→ C₃H₂O₄K₂(aq)+ MnO₂(aq)

A) C
B) H
C) O
D) K
E) Mn

Answer 3

C

Question 4

Balance the following redox reaction if it occurs in basic solution.What are the coefficients in front of Br₂ and OH⁻ in the balanced reaction?
Br₂(l)→ BrO₃⁻(aq)+ Br⁻(aq)

A) Br₂ = 1, OH⁻ = 2
B) Br₂ = 2, OH⁻ = 5
C) Br₂ = 3, OH⁻ = 3
D) Br₂ = 3, OH⁻ = 6
E) Br₂ = 1, OH⁻ = 6

Question 5

Balance the following redox reaction.What are the coefficients in front of H₂O and NO in the balanced reaction?
Zn(s)+ HNO₃(aq)→ Zn²⁺(aq)+ NO(g)

A) H₂O =4, NO = 2
B) H₂O =8, NO = 6
C) H₂O =1, NO = 3
D) H₂O =10, NO = 7
E) H₂O =5, NO = 9

Question 6

What element is being reduced in the following redox reaction?
H₂O₂(l)+ ClO₂(aq)→ ClO₂⁻(aq)+ O₂(g)

A) H
B) O
C) Cl
D) N
E) C

Question 7

What element is being oxidized in the following redox reaction?
H₂O₂(l)+ ClO₂(aq)→ ClO₂⁻(aq)+ O₂(g)

A) H
B) O
C) Cl
D) N
E) C

Question 8

Balance the following redox reaction if it occurs in acidic solution.What are the coefficients in front of H⁺ and Fe³⁺ in the balanced reaction?
Fe²⁺(aq)+ MnO₄⁻(aq)→ Fe³⁺(aq)+ Mn²⁺(aq)

A) H⁺ = 2, Fe³⁺ = 3
B) H⁺ = 8, Fe³⁺ = 5
C) H⁺ = 3, Fe³⁺ = 2
D) H⁺ = 5, Fe³⁺ = 1
E) H⁺ = 8, Fe³⁺ = 1

Question 9

What element is being oxidized in the following redox reaction?
MnO₄⁻(aq)+ H₂C₂O₄(aq)→ Mn²⁺(aq)+ CO₂(g)

A) C
B) O
C) Mn
D) H

Question 10

What element is being reduced in the following redox reaction?
C₃H₈O₂(aq)+ KMnO₄(aq)→ C₃H₂O₄K₂(aq)+ MnO₂(aq)

A) C
B) H
C) O
D) K
E) Mn

Question 11

Balance the following reaction in KOH.What are the coefficients in front of H₂O and KOH in the balanced reaction and list which side of the equation that H₂O and KOH appear?
C₃H₈O₂(aq)+ KMnO₄(aq)→ C₃H₂O₄K₂(aq)+ MnO₂(aq)

A) H₂O = 1, KOH = 4, right
B) H₂O = 4, KOH = 1, left
C) H₂O = 8, KOH = 2 right
D) H₂O = 3, KOH = 2, right
E) H₂O = 4, KOH = 2, left

Question 12

Balance the following reaction under basic conditions.What are the coefficients in front of H₂O and Cl^- in the balanced reaction?
Cl₂(aq)+ Br₂(l)→ BrO₃^-(aq)+ Cl^-(aq)

A) H₂O = 2, Cl^- = 2
B) H₂O = 2, Cl^- = 5
C) H₂O = 6, Cl^- = 10
D) H₂O = 4, Cl^- = 6
E) H₂O = 7, Cl^- = 3

Question 13

What element is being reduced in the following redox reaction?
C₃H₈O₂(aq)+ K₂Cr₂O₇(aq)→ C₃H₄O₄(aq)+ Cr⁺³(aq)

A) C
B) H
C) O
D) K
E) Cr

Question 14

What element is being reduced in the following redox reaction?
Cr(OH)₄⁻(aq)+ ClO⁻(aq)→ CrO₄^2-(aq)+ Cl⁻(aq)

A) Cr
B) O
C) H
D) Cl

Question 15

Balance the following redox reaction if it occurs in acidic solution.What are the coefficients in front of H₂C₂O₄ and H₂O in the balanced reaction?
MnO₄⁻(aq)+ H₂C₂O₄(aq)→ Mn²⁺(aq)+ CO₂(g)

A) H₂C₂O₄ = 5, H₂O = 8
B) H₂C₂O₄ = 1, H₂O = 1
C) H₂C₂O₄ = 5, H₂O = 1
D) H₂C₂O₄ = 1, H₂O = 4
E) H₂C₂O₄ = 3, H₂O = 2

Question 16

What element is being reduced in the following redox reaction?
MnO₄⁻(aq)+ H₂C₂O₄(aq)→ Mn²⁺(aq)+ CO₂(g)

A) C
B) O
C) Mn
D) H

Question 17

Balance the following redox reaction if it occurs in basic solution.What are the coefficients in front of ClO₂ and H₂O in the balanced reaction?
H₂O₂(l)+ ClO₂(aq)→ ClO₂⁻(aq)+ O₂(g)

A) ClO₂ = 1, H₂O = 1
B) ClO₂ = 1, H₂O = 2
C) ClO₂ = 4, H₂O = 3
D) ClO₂ = 4, H₂O = 2
E) ClO₂ = 2, H₂O = 2

Question 18

Balance the following redox reaction if it occurs in H₂SO₄.What are the coefficients in front of C₃H₈O₂ and H₂SO₄ in the balanced reaction?
C₃H₈O₂(aq)+ K₂Cr₂O₇(aq)→ C₃H₄O₄(aq)+ Cr₂(SO₄)₃(aq)

A) C₃H₈O₂ = 3, H₂SO₄ = 8
B) C₃H₈O₂ = 2, H₂SO₄ = 8
C) C₃H₈O₂ = 1, H₂SO₄ = 16
D) C₃H₈O₂ = 3, H₂SO₄ = 16
E) C₃H₈O₂ = 2, H₂SO₄ = 4

Question 19

What element is being oxidized in the following redox reaction?
C₃H₈O₂(aq)+ K₂Cr₂O₇(aq)→ C₃H₄O₄(aq)+ Cr⁺³(aq)

A) C
B) H
C) O
D) K
E) Cr

Question 20

What element is being oxidized in the following redox reaction?
Cr(OH)₄⁻(aq)+ ClO⁻(aq)→ CrO₄^2-(aq)+ Cl⁻(aq)

A) Cr
B) O
C) H
D) Cl

Question 21

Identify the location of oxidation in an electrochemical cell.

A) the anode
B) the cathode
C) the electrode
D) the salt bridge
E) the socket

Question 22

Use the standard half-cell potentials listed below to calculate the standard cell potential for the following reaction occurring in an electrochemical cell at 25°C.(The equation is balanced.) Sn(s)+ 2 Ag⁺(aq)→ Sn²⁺(aq)+ 2 Ag(s)
Sn²⁺(aq)+ 2 e⁻ → Sn(s)E° = -0.14 V
Ag⁺(aq)+ e⁻ → Ag(s)E° = +0.80 V

A) +1.74 V
B) +0.94 V
C) +1.08 V
D) -1.08 V
E) -1.74 V

Question 23

What statement is NOT true about standard electrode potentials?

A) E°_cell ^{is positive for spontaneous reactions.}
B) Electrons will flow from more negative electrode to more positive electrode.
C) The electrode potential of the standard hydrogen electrode is exactly zero.
D) E°_cell is the difference in voltage between the anode and the cathode.
E) The electrode in any half-cell with a greater tendency to undergo reduction is positively charged relative to the standard hydrogen electrode and therefore has a positive E°.

Question 24

Define a salt bridge.

A) A pathway, composed of salt water, that ions pass through.
B) A pathway in which no ions flow.
C) A pathway between the cathode and anode in which ions are reduced.
D) A pathway between the cathode and anode in which ions are oxidized.
E) A pathway by which counter ions can flow between the half-cells without the solutions in the half-cell totally mixing.

Question 25

Use the tabulated half-cell potentials to calculate ΔG° for the following balanced redox reaction. 3 I₂(s)+ 2 Fe(s)→ 2 Fe³⁺(aq)+ 6 I⁻(aq)

A) -1.1 × 10² kJ
B) +4.9 × 10¹ kJ
C) -9.7 × 10¹ kJ
D) +2.3 × 10² kJ
E) -3.3 × 10² kJ

Question 26

Which of the following reactions would be the most spontaneous at 298 K?

A) A + 2 B → C; E°_cell = +0.98 V
B) A + B → 2 C; E°_cell = -0.030 V
C) A + B → 3 C; E°_cell = +0.15 V
D) A + B → C; E°_cell = +1.22 V
E) More information is needed to determine.

Question 27

Use the tabulated half-cell potentials to calculate ΔG° for the following redox reaction. 2 Ag(s)+ Pb²⁺(aq)→ Ag⁺(aq)+ Pb(s)

A) 179 kJ
B) 89.5 kJ
C) -328 kJ
D) -107 kJ
E) 212 kJ

Question 28

Use the tabulated half-cell potentials to calculate ΔG° for the following redox reaction. 2 Al(s)+ 3 Mg²⁺(aq)→ 2 Al³⁺(aq)+ 3 Mg(s)

A) +4.1 × 10² kJ
B) +1.4 × 10² kJ
C) -2.3 × 10² kJ
D) -7.8 × 10² kJ
E) +6.8 × 10² kJ

Question 29

Use the standard half-cell potentials listed below to calculate the standard cell potential for the following reaction occurring in an electrochemical cell at 25°C.(The equation is balanced.) 3 Cl₂(g)+ 2 Fe(s)→ 6 Cl⁻(aq)+ 2 Fe³⁺(aq)
Cl₂(g)+ 2 e⁻ → 2 Cl⁻(aq)E° = +1.36 V
Fe³⁺(aq)+ 3 e⁻ → Fe(s)E° = -0.04 V

A) +4.16 V
B) -1.40 V
C) -1.32 V
D) +1.32 V
E) +1.40 V

Question 30

Determine the cell notation for the redox reaction given below. 3 Cl₂(g)+ 2 Fe(s)→ 6 Cl⁻(aq)+ 2 Fe³⁺(aq)

A) Cl₂(g) ∣ Cl⁻(aq) ∣ Pt Fe(s) ∣ Fe³⁺(aq)
B) Cl⁻(aq) ∣ Cl₂(g) ∣ Pt Fe³⁺(aq) ∣ Fe(s)
C) Fe³⁺(aq) ∣ Fe(s) Cl⁻(aq) ∣ Cl₂(g) ∣ Pt
D) Fe(s) ∣ Cl₂(g) Fe³⁺(aq) ∣ Cl⁻(aq) ∣ Pt
E) Fe(s) ∣ Fe³⁺(aq) Cl₂(g) ∣ Cl⁻(aq) ∣ Pt

Question 31

Use the standard half-cell potentials listed below to calculate the standard cell potential for the following reaction occurring in an electrochemical cell at 25°C.(The equation is balanced.) 2 K(s)+ I₂(s)→ 2 K⁺(aq)+ 2 I⁻(aq)
K⁺(aq)+ e⁻ → K(s)E° = -2.93 V
I₂(s)+ 2 e⁻ → 2 I⁻(aq)E° = +0.54 V

A) +6.40 V
B) +1.85 V
C) -5.32 V
D) +3.47 V
E) +5.32 V

Question 32

Use the standard half-cell potentials listed below to calculate the standard cell potential for the following reaction occurring in an electrochemical cell at 25°C.(The equation is balanced.) Pb(s)+ Br₂(l)→ Pb²⁺(aq)+ 2 Br⁻(aq)
Pb²⁺(aq)+ 2 e⁻ → Pb(s)E° = -0.13 V
Br₂(l)+ 2 e⁻ → 2 Br⁻(aq)E° = +1.07 V

A) +1.20 V
B) +0.94 V
C) -0.94 V
D) -1.20 V
E) -0.60 V

Question 33

Identify the characteristics of a spontaneous reaction.

A) ΔG° < 0
B) ΔE°_cell > 0
C) K > 1
D) all of the above
E) none of the above

Question 34

Use the standard half-cell potentials listed below to calculate the standard cell potential for the following reaction occurring in an electrochemical cell at 25°C.(The equation is balanced.) 2F₂(g)+ Mn(s)→ 4 F⁻(aq)+ Mn²⁺(aq)
F₂(g)+ e⁻ → 2 F⁻(aq)E° = +2.87 V
Mn²⁺(aq)+ 2 e⁻ → Mn(s)E° = -1.18 V

A) 1.69 V
B) 4.050 V
C) -4.050 V
D) -4.060 V
E) +2.87 V

Question 35

Balance the following redox reaction if it occurs in basic solution.What are the coefficients in front of Cr(OH)₄⁻ and ClO⁻ in the balanced reaction?
Cr(OH)₄⁻(aq)+ ClO⁻(aq)→ CrO₄^2-(aq)+ Cl⁻(aq)

A) Cr(OH)₄⁻ = 2, ClO⁻ = 3
B) Cr(OH)₄⁻ = 1, ClO⁻ = 1
C) Cr(OH)₄⁻ = 1, ClO⁻ = 2
D) Cr(OH)₄⁻ = 2, ClO⁻ = 6
E) Cr(OH)₄⁻ = 6, ClO⁻ = 5

Question 36

How many electrons are transferred in the following reaction? (The reaction is unbalanced.)
I₂(s)+ Fe(s)→ Fe³⁺(aq)+ I⁻(aq)

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

Question 37

Use the standard half-cell potentials listed below to calculate the standard cell potential for the following reaction occurring in an electrochemical cell at 25°C.(The equation is balanced.) Mg(s)+ Cu²⁺(aq)→ Cu(s)+ Mg²⁺(aq)
Mg²⁺(aq)+ 2 e⁻ → Mg(s)E° = -2.38 V
Cu²⁺(aq)+ 2 e⁻ → Cu(s)E° = +0.34 V

A) +2.04 V
B) -2.04 V
C) +2.72 V
D) -1.36 V
E) +1.36 V

Question 38

Identify the location of reduction in an electrochemical cell.

A) the anode
B) the cathode
C) the electrode
D) the salt bridge
E) the socket

Question 39

Which of the following is the weakest oxidizing agent?

A) H₂O₂(aq)
B) Fe³⁺(aq)
C) ClO₂(g)
D) F^-(s)
E) Fe(s)

Question 40

Use the tabulated half-cell potentials to calculate ΔG° for the following balanced redox reaction. Pb²⁺(aq)+ Cu(s)→ Pb(s)+ Cu²⁺(aq)

A) -41 kJ
B) -0.47 kJ
C) +46 kJ
D) +91 kJ
E) -21 kJ

Question 41

Identify the battery that is in most automobiles.

A) dry-cell battery
B) lithium ion battery
C) lead-acid storage battery
D) NiCad battery
E) fuel cell

Question 42

Which battery uses the metal with the least dense metal?

A) nickel-metal hydride
B) lithium-ion
C) nickel-cadmium
D) lead acid
E) dry cell

Question 43

Calculate the cell potential for the following reaction that takes place in an electrochemical cell at 25°C. Sn(s)∣ Sn²⁺(aq,0.022 M) Ag⁺(aq,2.7 M)∣ Ag(s)

A) +1.01 V
B) -0.83 V
C) +1.31 V
D) +0.01 V
E) -0.66 V

Question 44

Calculate the cell potential for the following reaction that takes place in an electrochemical cell at 25°C. Fe(s)∣ Fe³⁺(aq,0.0011 M) Fe³⁺(aq,2.33 M)∣ Fe(s)

A) +0.066 V
B) -0.036 V
C) 0.00 V
D) -0.099 V
E) +0.20 V

Question 45

Calculate the cell potential for the following reaction that takes place in an electrochemical cell at 25°C. Al(s)∣ Al³⁺(aq,0.115 M) Al³⁺(aq,3.89 M)∣ Al(s)

A) +1.66 V
B) +0.060 V
C) 0.00 V
D) +0.090 V
E) +0.030 V

Question 46

Which of the following reactions would have the smallest value of K at 298 K?

A) A + B → C; E°_cell = +1.22 V
B) A + 2 B → C; E°_cell = +0.98 V
C) A + B → 2 C; E°_cell = -0.030 V
D) A + B → 3 C; E°_cell = +0.15 V
E) More information is needed to determine.

Question 47

Identify the components of a fuel cell.

A) nickel-metal hydride
B) lithium ion
C) hydrogen-oxygen
D) nickel-cadmium
E) zinc-manganese

Question 48

All of the following are examples of rechargeable batteries EXCEPT

A) NiCad batteries.
B) NiMH batteries.
C) dry cell batteries.
D) lead-acid batteries.
E) lithium ion batteries.

Question 49

Use the tabulated half-cell potentials to calculate the equilibrium constant (K)for the following balanced redox reaction at 25°C. 2 Al(s)+ 3 Mg²⁺(aq)→ 2 Al³⁺(aq)+ 3 Mg(s)

A) 1.1 × 10⁷²
B) 8.9 × 10^-73
C) 1.1 × 10^-72
D) 1.0 × 10²⁴
E) 4.6 × 10³¹

Question 50

Calculate the cell potential for the following reaction that takes place in an electrochemical cell at 25°C. Mg(s)∣ Mg²⁺(aq,2.74 M) Cu²⁺(aq,0.0033 M)∣ Cu(s)

A) -2.80 V
B) +2.62 V
C) +2.71 V
D) +2.12 V
E) -1.94 V

Question 51

Describe how water can be a good conductor of current.

A) use pure water
B) heat the water
C) add salt
D) chill the water
E) vaporize the water

Question 52

Identify the battery that is used as a common flashlight battery.

A) dry-cell battery
B) lithium ion battery
C) lead-acid storage battery
D) NiCad battery
E) fuel cell

Question 53

What mass of silver can be plated onto an object in 33.5 minutes at 8.70 A of current?
Ag⁺(aq)+ e⁻ → Ag(s)

A) 19.6 g
B) 0.326 g
C) 9.78 g
D) 3.07 g
E) 0.102 g

Question 54

Use the tabulated half-cell potentials to calculate the equilibrium constant (K)for the following balanced redox reaction at 25°C. 3 I₂(s)+ 2 Fe(s)→ 2 Fe³⁺(aq)+ 6 I⁻(aq)

A) 3.5 × 10^-59
B) 1.1 × 10¹⁷
C) 6.1 × 10⁵⁸
D) 8.9 × 10^-18
E) 1.7 × 10²⁹

Question 55

Calculate the cell potential for the following reaction that takes place in an electrochemical cell at 25°C. Cu(s)∣ Cu²⁺(aq,0.0032 M) Cu²⁺(aq,4.48 M)∣ Cu(s)

A) 0.00 V
B) +0.093 V
C) +0.34 V
D) +0.186 V
E) +0.052 V

Question 56

Calculate the cell potential for the following reaction that takes place in an electrochemical cell at 25°C. Mn(s)∣ Mn²⁺(aq,1.28 M) Ag⁺(aq,0.000837 M)∣ Ag(s)

A) 1.98 V
B) -1.28 V
C) 0.00 V
D) 1.79 V
E) -0.84 V

Question 57

Identify the battery type that has a high overcharge tolerance.

A) NiCad
B) Li ion
C) NiMH
D) lead storage
E) none of the above

Question 58

What is the reaction at the anode in nickel-cadmium battery?

A) Cadmium is reduced.
B) Nickel(II) hydroxide is produced.
C) Cadmium is oxidized.
D) Nickel is oxidized.
E) Nickel is reduced.

Question 59

Calculate the cell potential for the following reaction that takes place in an electrochemical cell at 25°C. Sn(s)∣ Sn²⁺(aq,1.8 M) Ag⁺(aq,0.055 M)∣ Ag(s)

A) -0.94 V
B) -0.85 V
C) +1.02 V
D) +0.98 V
E) +0.86 V

Question 60

Use the tabulated half-cell potentials to calculate the equilibrium constant (K)for the following balanced redox reaction at 25°C. Pb²⁺(aq)+ Cu(s)→ Pb(s)+ Cu²⁺(aq)

A) 7.9 × 10^-8
B) 8.9 × 10⁷
C) 7.9 × 10¹⁵
D) 1.1 × 10^-22
E) 1.1 × 10^-8

Question 61

Identify a component in the formation of rust.

A) salt
B) moisture
C) acid
D) all of the above
E) none of the above

Question 62

What mass of aluminum can be plated onto an object in 755 minutes at 5.80 A of current?

A) 73.5 g
B) 24.5 g
C) 220. g
D) 147 g
E) 8.17 g

Question 63

What element is being oxidized in the following redox reaction?
Ni²⁺(aq)+ NH₄⁺(aq)→ Ni(s)+ NO₃⁻(aq)

A) Ni
B) N
C) H
D) O

Question 64

Use the standard half-cell potentials listed below to calculate the standard cell potential for the following reaction occurring in an electrochemical cell at 25°C. Cu(s)+ Mg²⁺(aq)→ Mg(s)+ Cu²⁺(aq)
Mg²⁺(aq)+ 2 e⁻ → Mg(s)E° = -2.38 V
Cu²⁺(aq)+ 2 e⁻ → Cu(s)E° = +0.34 V

A) +2.04 V
B) -2.04 V
C) +2.72 V
D) -2.72 V
E) -1.36 V

Question 65

To prevent rust,nails are coated with

A) zinc.
B) salt.
C) calcium.
D) sodium.
E) lithium.

Question 66

Balance the following redox reaction if it occurs in basic solution.What are the coefficients in front of SO₃^2- and MnO₄⁻ in the balanced reaction?
SO₃^2-(aq)+ MnO₄⁻(aq)→ SO₄^2-(aq)+ MnO₂(s)

A) SO₃^2- = 2, MnO₄⁻ = 3
B) SO₃^2- = 1, MnO₄⁻ = 1
C) SO₃^2- = 4, MnO₄⁻ = 2
D) SO₃^2- = 2, MnO₄⁻ = 5
E) SO₃^2- = 3, MnO₄⁻ = 2

Question 67

Balance the following redox reaction if it occurs in acidic solution.What are the coefficients in front of NO₃^-and Sn²⁺ in the balanced reaction?
NO₃⁻(aq)+ Sn²⁺(aq)→ Sn⁴⁺(aq)+ NO(g)

A) NO₃⁻ = 3, Sn²⁺ = 2
B) NO₃⁻ = 2, Sn²⁺ = 3
C) NO₃⁻ = 4, Sn²⁺ = 9
D) NO₃⁻ = 1, Sn²⁺ = 1
E) NO₃⁻ = 3, Sn²⁺ = 5

Question 68

Describe the reactions during the electrolysis of water in an electrolytic cell.

A) Oxygen is reduced and hydrogen is oxidized.
B) Oxygen and hydrogen are both oxidized.
C) Oxygen and hydrogen are both reduced.
D) Oxygen is oxidized and hydrogen is reduced.
E) Neither oxygen or hydrogen are oxidized or reduced.

Question 69

Predict the species that will be reduced first if the following mixture of molten salts undergoes electrolysis. Zn²⁺,Fe³⁺,Mg²⁺,Br^-,I^-

A) Zn²⁺
B) Mg²⁺
C) Br^-
D) Fe³⁺
E) I^-

Question 70

Predict the species that will be oxidized first if the following mixture of molten salts undergoes electrolysis. Cu²⁺,Mg²⁺,Cl⁻,Br⁻,F⁻

A) Cl⁻
B) F⁻
C) Cu²⁺
D) Mg²⁺
E) Br⁻

Question 71

Identify oxidation.

A) increase in oxidation number
B) loss of electrons
C) gain of electrons
D) loss of protons
E) both A and B

Question 72

How many electrons are transferred in the following reaction? (The reaction is unbalanced.)
Mg²⁺(aq)+ Li(s)→ Mg(s)+ Li⁺(aq)

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

Question 73

Determine the redox reaction represented by the following cell notation. Mn(s)∣ Mn²⁺(aq) Cu²⁺(aq)∣ Cu(s)

A) Cu(s) + Mn²⁺(aq) → Mn(s) + Cu²⁺(aq)
B) Mn(s) + Cu²⁺(aq) → Cu(s) + Mn²⁺(aq)
C) 2 Mn(s) + Cu²⁺(aq) → Cu(s) + 2 Mn²⁺(aq)
D) 2 Cu(s) + Mn²⁺(aq) → Mn(s) + 2 Cu²⁺(aq)
E) 3 Mn(s) + 2 Cu²⁺(aq) → 2 Cu(s) + 3 Mn²⁺(aq)

Question 74

Balance the following redox reaction if it occurs in basic solution.What are the coefficients in front of Al and Br₂ in the balanced reaction?
Al(s)+ Br₂(g)→ Al³⁺(aq)+ Br^-(aq)

A) Al = 2, Br₂ = 3
B) Al = 2, Br₂ = 6
C) Al = 1, Br₂ = 1
D) Al = 2, Br₂ = 1
E) Al = 3, Br₂ = 2

Question 75

Nickel can be plated from aqueous solution according to the following half reaction.How long would it take (in min)to plate 29.6 g of nickel at 4.7 A?
Ni²⁺(aq)+ 2 e⁻ → Ni(s)

A) 1.7 × 10² min
B) 5.9 × 10² min
C) 3.5 × 10² min
D) 4.8 × 10² min
E) 6.2 × 10² min

Question 76

Predict the species that will be reduced first if the following mixture of molten salts undergoes electrolysis. Na⁺,Ca²⁺,Cl⁻,Br⁻,F⁻

A) Na⁺
B) Cl⁻
C) Ca²⁺
D) Br⁻
E) F⁻

Question 77

Balance the following redox reaction if it occurs in acidic solution.What are the coefficients in front of Ni and Ag⁺ in the balanced reaction?
Ni(s)+ Ag⁺(aq)→ Ag(s)+ Ni²⁺(aq)

A) Ni = 1, Ag⁺ = 2
B) Ni = 1, Ag⁺ = 1
C) Ni = 2, Ag⁺ = 1
D) Ni = 2, Ag⁺ = 2
E) Ni = 3, Ag⁺ = 1

Question 78

Balance the following redox reaction if it occurs in acidic solution.What are the coefficients in front of Sn and H⁺ in the balanced reaction?
Sn²⁺(aq)+ NH₄⁺(aq)→ Sn(s)+ NO₃⁻(aq)

A) Sn = 1, H⁺ = 8
B) Sn = 1, H⁺ = 4
C) Sn = 4, H⁺ = 10
D) Sn = 2, H⁺ = 4
E) Sn = 3, H⁺ = 5

Question 79

Use the standard half-cell potentials listed below to calculate the standard cell potential for the following reaction occurring in an electrochemical cell at 25°C. 4 F⁻(aq)+ Mn²⁺(aq)→ 2F₂(g)+ Mn(s)
F₂(g)+ 2e⁻ → 2 F⁻(aq)E° = +2.87 V
Mn²⁺(aq)+ 2 e⁻ → Mn(s)E° = -1.18 V

A) 1.69 V
B) 4.05 V
C) -4.05 V
D) +2.87 V

Question 80

How many electrons are transferred in the following reaction? (The reaction is unbalanced.)
Ba(s)+ Cr³⁺(aq)→ Cr(s)+ Ba²⁺(aq)

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