Deck 20: Electrochemistry

Question 1

An electrolyte is

A)a solid that conducts electrical energy.
B)an inert electrode that conducts electrical energy.
C)a metal that conducts electrical energy through a solution.
D)a compound that conducts electricity either in solution or in the molten state.
E)a solvent that conducts electricity.

Answer 1

a compound that conducts electricity either in solution or in the molten state.

Question 2

Anions

A)are charged ions that move toward the anode of a galvanic or electrolytic cell.
B)are charged ions that move toward the negative electrode of an electrolytic cell.
C)are charged ions that move toward the north pole of a magnetic field.
D)are positively charged ions that result from electrical discharge in a liquid solution.
E)are ions that attach themselves to any electrode to react chemically during electrolytic.

Answer 2

are charged ions that move toward the anode of a galvanic or electrolytic cell.

Question 3

Cations

A)are negatively charged ions that result from electrical discharge in a liquid solution.
B)are charged ions that move toward the cathode of a galvanic or electrolytic cell.
C)are charged ions that move toward the positive electrode of an electrolytic cell.
D)are charged ions that move toward the south pole of a magnetic field.
E)are ions that attach themselves to any electrode to react chemically during electrolysis.

Answer 3

are charged ions that move toward the cathode of a galvanic or electrolytic cell.

Question 4

A galvanic cell has two electrodes. Which statement is correct?

A)Oxidation takes place at the anode, which is positively charged.
B)Oxidation takes place at the anode, which is negatively charged.
C)Oxidation takes place at the cathode, which is positively charged.
D)Oxidation takes place at the cathode, which is negatively charged.
E)Oxidation take place at the dynode, which is uncharged.

Question 5

A galvanic cell has two electrodes. Which statement is correct?

A)Reduction takes place at the anode, which is positively charged.
B)Reduction takes place at the anode, which is negatively charged.
C)Reduction takes place at the cathode, which is positively charged.
D)Reduction takes place at the cathode, which is negatively charged.
E)Reduction takes place at the dynode, which is uncharged.

Question 6

A galvanic cell consists of a Cu(s)|Cu²⁺(aq)half-cell and a Zn(s)|Zn²⁺(aq)half-cell, connected by a salt bridge. Oxidation occurs in the zinc half-cell. The cell can be represented in standard notation as:

A)Cu(s)|Cu²⁺(aq)|Zn(s)|Zn²⁺(aq)
B)Zn(s)|Zn²⁺(aq)||Cu(s)|Cu²⁺(aq)
C)Cu²⁺(aq)|Cu(s)||Zn(s)|Zn²⁺(aq)
D)Zn(s)|Zn²⁺(aq)||Cu²⁺(aq)|Cu(s)
E)Zn²⁺(aq)|Zn(s)||Cu(s)|Cu²⁺(aq)

Question 7

A galvanic cell consists of an Ag(s)|Ag⁺(aq)half-cell and a Zn(s)|Zn²⁺(aq)half-cell connected by a salt bridge. Oxidation occurs in the zinc half-cell. The cell can be represented in standard notation as

A)Ag(s)|Ag⁺(aq)|Zn(s)|Zn²⁺(aq)
B)Zn(s)|Zn²⁺(aq)||Ag(s)|Ag⁺(aq)
C)Ag⁺(aq)|Ag(s)||Zn(s)|Zn²⁺(aq)
D)Zn²⁺(aq)|Zn(s)||Ag(s)|Ag⁺(aq)
E)Zn(s)|Zn²⁺(aq)||Ag⁺(aq)|Ag(s)

Question 8

A galvanic cell consists of a Cd(s)|Cd²⁺(aq)half-cell and a Zn(s)|Zn²⁺(aq)half-cell connected by a salt bridge. Reduction occurs in the cadmium half-cell. The cell can be represented in standard notation as:

A)Cd(s)|Cd²⁺(aq)|Zn(s)|Zn²⁺(aq)
B)Zn(s)|Zn²⁺(aq)||Cd(s)|Cd²⁺(aq)
C)Zn(s)|Zn²⁺(aq)||Cd²⁺(aq)|Cd(s)
D)Zn²⁺(aq)|Zn(s)||Cd(s)|Cd²⁺(aq)
E)Cd²⁺(aq)|Cd(s)||Zn(s)|Zn²⁺(aq)

Question 9

A galvanic cell consists of a Cu(s)|Cu²⁺(aq)half-cell and a Cd(s)|Cd²⁺(aq)half-cell connected by a salt bridge. Oxidation occurs in the cadmium half-cell. The cell can be represented in standard notation as:

A)Cu(s)|Cu²⁺(aq)|Cd(s)|Cd²⁺(aq)
B)Cd(s)|Cd²⁺(aq)||Cu²⁺(aq)|Cu(s)
C)Cd²⁺(aq)|Cd(s)||Cu(s)|Cu²⁺(aq)
D)Cd(s)|Cd²⁺(aq)||Cu(s)|Cu²⁺(aq)
E)Cu²⁺(aq)|Cu(s)||Cd(s)|Cd²⁺(aq)

Question 10

A galvanic cell consists of an Ag(s)|Ag⁺(aq)half-cell and a Cu(s)|Cu²⁺(aq)half-cell connected by a salt bridge. The cell can be represented in standard notation as:

A)Ag(s)|Ag⁺(aq)|Cu(s)|Cu²⁺(aq)
B)Cu(s)|Cu²⁺(aq)||Ag(s)|Ag⁺(aq)
C)Ag⁺(aq)|Ag(s)||Cu(s)|Cu²⁺(aq)
D)Cu²⁺(aq)|Cu(s)||Ag(s)|Ag⁺(aq)
E)Cu(s)|Cu²⁺(aq)||Ag⁺(aq)|Ag(s)

Question 11

A galvanic cell consists of an Ag(s)|Ag⁺(aq)half-cell and a Cu(s)|Cu²⁺(aq)half-cell connected by a salt bridge. The cell can be represented in standard notation as: Cu(s)|Cu²⁺(aq)||Ag⁺(aq)|Ag(s).Which species is being reduced?

A)Ag⁺(aq)
B)Cu²⁺(aq)
C)Ag(s)
D)Cu(s)
E)Cu⁺(aq)

Question 12

The electrode for which the standard reduction potential of 0.00 V is assigned uses the half-reaction:

A)Zn²⁺(aq)+ 2e^- Zn(s)
B)Cu²⁺(aq)+ 2e^- Cu(s)
C)Ag⁺(aq)+ e^- Ag(s)
D)2 H⁺(aq)+ 2e^- H₂(g)
E)2 NH₄⁺(aq)+ 2e^- H₂(g)+ 2 NH₃(g)

Question 13

Using these metal ion/metal standard reduction potentials Calculate the standard cell potential for the cell whose reaction is:
Cu²⁺(aq)+ Cd(s) $\rarr$ Cd²⁺(aq)+ Cu(s)

A)+0.76 V
B)+0.06 V
C)-0.06 V
D)+0.74 V
E)+0.20 V

Question 14

Using these metal ion/metal standard reduction potentials
Calculate the standard cell potential for the cell whose reaction is:
Ni²⁺(aq)+ Zn(s) $\rarr$ Zn²⁺(aq)+ Ni(s)

A)+0.51 V
B)-1.02 V
C)-1.01 V
D)+1.01 V
E)-0.51 V

Question 15

Using these metal ion/metal standard reduction potentials
Calculate the standard cell potential for the cell whose reaction is:
Fe²⁺(aq)+ Cr(s) $\rarr$ Fe(s)+ Cr³⁺(aq)

A)-0.30 V
B)-1.18 V
C)+0.30 V
D)+0.16 V
E)-0.16 V

Question 16

Using these metal ion/metal reaction potentials: Calculate the standard cell potential for the cell whose reaction is:
Co(s)+ Cu²⁺(aq) $\rarr$ Co²⁺(aq)+ Cu(s)

A)-0.06 V
B)+0.06 V
C)-0.62 V
D)+0.62 V
E)+0.68 V

Question 17

Using the standard reduction potentials: Calculate the value of E°_cell for the reaction:
2Au(s)+ 3Ca²⁺(aq) $\rarr$ 2Au³⁺(aq)+ 3Ca(s)

A)-1.43 V
B)+1.34 V
C)-4.18 V
D)+4.18 V
E)-1.34 V

Question 18

Using the standard reduction potentials:: Calculate the value of E°_cell for the cell with the reaction:2Cr(s)+ 3Cl₂(g) $\rarr$ 2Cr³⁺(aq)+ 6Cl^-(aq)

A)-0.96 V
B)+0.96 V
C)+2.10 V
D)-2.10 V
E)+0.98 V

Question 19

For the reaction, 2 Cr²⁺(aq)+ Cl₂(g) 2 Cr³⁺(aq)+ 2 Cl^-(aq), the value of E°_cell is1.78 V. What is the value of E°_cell for the following reaction?
Cr³⁺(aq)+ Cl^-(aq) $\rarr$ Cr²⁺(aq)+ ½ Cl₂(g)

A)-1.78 V
B)+0.89 V
C)+1.78 V
D)-0.89 V
E)-3.56 V

Question 20

The cell described by the net reaction:2U(s)+ 3Cl₂(g) 6 Cl^-(aq)+ 2U³⁺(aq)has a standard cell potential of 3.16 Vs. Using the standard reduction potential value shown for:Cl₂(g)+ 2 e^- 2 Cl^-(aq)E° = +1.36 V determine the standard reduction potential of the U³⁺(aq)|U(s)half-cell

A)-1.80 V
B)+1.80 V
C)-1.96 V
D)-4.52 V
E)+4.52 V

Question 21

Consider this electrochemical cell:Pt | Pu³⁺(aq), Pu⁴⁺(aq)|| Cl₂(g), Cl^-(aq)| Pt Given that the standard cell potential is 0.35 V, what is the standard reduction potential E°(Pu⁴⁺/Pu³⁺) $\rarr$

A)2.37 V
B)1.71 V
C)1.01 V
D)-1.71 V
E)-1.01 V

Question 22

The cell described by the reaction,2 Co³⁺(aq)+ 2 Cl^-(aq) 2 Co²⁺(aq)+ Cl₂(g)has a standard potential of 0.46 V. Using the standard reduction potential value shown for determine a value for the standard reduction potential of the cathode half-cell.

A)-0.90 V
B)+0.90 V
C)+0.91 V
D)-1.82 V
E)+1.82 V

Question 23

Consider these metal ion/metal standard reduction potentials Based on the data above, which one of the species below is the best reducing agent?

A)Co(s)
B)Zn(s)
C)Cu²⁺(aq)
D)Cu(s)
E)Ag(s)

Question 24

Using the standard reduction potentials Calculate the value of E°_cell for the cell with the reaction:
3 Mg(s)+ 2 NO₃^-(aq)+ 8 H⁺(aq) $\rarr$ 3 Mg²⁺(aq)+ 2 NO(g)+ 4 H₂O

A)+1.41 V
B)-1.41 V
C)+3.33 V
D)+8.46 V
E)-8.46 V

Question 25

Using the standard reduction potentials Calculate the value of E°_cell for the cell with the following reaction.
Ni²⁺(aq)+ 2 Fe²⁺(aq) $\rarr$ Ni(s)+ 2 Fe³⁺(aq)

A)+0.52 V
B)-1.02 V
C)+2.81 V
D)+1.02 V
E)-2.81 V

Question 26

Consider these metal ion/metal standard reduction potentials Based on the data above, which species is the best oxidizing agent?

A)Co²⁺(aq)
B)Zn²⁺(aq)
C)Cu²⁺(aq)
D)Cd²⁺(aq)
E)Ag⁺(aq)

Question 27

Consider these metal ion/metal standard reduction potentials Based on the data above, which species is the best reducing agent?

A)Cd(s)
B)Ag(s)
C)Ni(s)
D)Zn(s)
E)Cu(s)

Question 28

Consider these metal ion/metal standard reduction potentials Based on the data above, which species is the best oxidizing agent?

A)Cd²⁺(aq)
B)Zn²⁺(aq)
C)Co²⁺(aq)
D)Cu²⁺(aq)
E)Ni²⁺(aq)

Question 29

Consider these metal ion/metal standard reduction potentials Based on the data above, which species is the best reducing agent?

A)Co(s)
B)Cu(s)
C)Cd²⁺(aq)
D)Zn²⁺(aq)
E)Zn(s)

Question 30

Consider these metal ion/metal standard reduction potentials Based on the data above, which species is the best reducing agent?

A)Ni(s)
B)Na(s)
C)Au(s)
D)Cu(s)
E)Al(s)

Question 31

Which statement is true concerning a galvanic cell?

A)E° for the cell is always positive.
B)E° for the cell is always negative.
C)The standard reduction potential for the anode reaction is always positive.
D)The standard reduction potential for the anode reaction is always negative.
E)The standard reduction potential for the cathode reaction is always positive.

Question 32

A certain electrochemical cell has a cell potential of +0.34 V. Which of the following is a true statement about the electrochemical reaction?

A)The reaction favors the formation of reactants and would be considered an electrolytic cell.
B)The reaction favors the formation of reactants and would be considered a galvanic cell.
C)The reaction favors the formation of products and would be considered an electrolytic cell.
D)The reaction is at equilibrium and is a galvanic cell.
E)The reaction favors the formation of products and would be considered a galvanic cell.

Question 33

A unit of electrical energy is the

A)ampere.
B)coulomb.
C)joule.
D)volt.
E)watt.

Question 34

Consider the following reaction: 2Fe²⁺(aq)+ Cu²⁺ $\rarr$ 2Fe³⁺(aq)+ Cu.When the ion concentrations change to the point where the reaction comes to equilibrium, what would be the cell voltage?

A)1.11 V
B)-0.43 V
C)0.0 V
D)0.43 V
E)0.78 V

Question 35

A unit of electrical charge used is the

A)ampere.
B)coulomb.
C)V.
D)joule.
E)watt.

Question 36

The Faraday constant is equal to the ________ on 1 mole of electrons.

A)capacitance
B)current
C)power
D)pressure
E)electrical charge

Question 37

One mole of electrical charge contains

A)4.184 joules.
B)3,600 coulombs.
C)23,060 joules.
D)96,485 coulombs.
E)3.47 × 10⁸ coulombs.

Question 38

A galvanic cell is composed of these two half-cells, with the standard reduction potentials shown: What is the standard free energy change for the cell reaction of this galvanic cell?

A)-12 kJ
B)+12 kJ
C)-23 kJ
D)+23 kJ
E)-46 kJ

Question 39

A galvanic cell is composed of these two half-cells, with the standard reduction potentials shown: What is the standard free energy ( $\Delta$ G°)change for the cell reaction of this galvanic cell?

A)+12 kJ
B)-12 kJ
C)+143 kJ
D)-143 kJ
E)-71 kJ

Question 40

A galvanic cell is composed of these two half-cells, with the standard reduction potentials shown: What is the standard free energy change ( $\Delta$ G°)for the cell reaction of this galvanic cell?

A)69 kJ
B)+69 kJ
C)-224 kJ
D)+224 kJ
E)-35 kJ

Question 41

A galvanic cell is composed of these two half-cells, with the standard reduction potentials shown: What is the standard free energy ( $\Delta$ G°)change for the cell reaction of this galvanic cell?

A)-88.8 kJ
B)-178 kJ
C)-266 kJ
D)-295 kJ
E)-590 kJ

Question 42

A galvanic cell is composed of these two half-cells, with the standard reduction potentials shown: What is the standard free energy ( $\Delta$ G°)change for the cell reaction of this galvanic cell?

A)-806 kJ
B)-1.22 × 10³ kJ
C)-706 kJ
D)-540 kJ
E)-600 kJ

Question 43

A galvanic cell is composed of these two half-cells, with the standard reduction potentials shown: What is the standard free energy ( $\Delta$ G°)change for the cell reaction of this galvanic cell?

A)-2.22 × 10² kJ
B)-3.14 × 10² kJ
C)-1.74 × 10² kJ
D)-6.02 × 10² kJ
E)-1.20 × 10² kJ

Question 44

A galvanic cell is composed of these two half-cells, with the standard reduction potentials shown: What is the standard free energy ( $\Delta$ G°)change for the cell reaction of this galvanic cell?

A)-2.49 × 10² kJ
B)-3.21 × 10² kJ
C)-6.43 × 10² kJ
D)-5.32 × 10² kJ
E)-4.31 × 10² kJ

Question 45

Using the standard reduction potentials Calculate the standard free energy ( $\Delta$ G°)change for the cell reaction:
2 Au(s)+ 3 Ca²⁺(aq) $\rarr$ 2 Au³⁺(aq)+ 3 Ca(s)

A)2420 kJ
B)388 kJ
C)-766 kJ
D)766 kJ
E)-1210 kJ

Question 46

Using these metal ion/metal standard reduction potentials Calculate the standard free energy ( $\Delta$ G°)change for the cell reaction:Fe²⁺(aq)+ Cr(s) $\rarr$ Fe(s)+ Cr³⁺(aq)

A)-92.6 kJ
B)-86.8 kJ
C)683.1 kJ
D)-57.9 kJ
E)-173.7 kJ

Question 47

Using the reduction potentials given, calculate the equilibrium constant, K, at 25°C for the reaction,

A)1.66
B)6.4
C)3.2
D)6.1 × 10^-4
E)1.6 × 10⁴

Question 48

The equilibrium constant, K_c, was found to be 1.2 × 10³ at 25°C for the reaction,2X(s)+ Cu²⁺(aq) 2X⁺(aq)+ Cu(s)Using the following reduction potential for copper, what is the reduction potential for the other half reaction involving the substance X?

A)-0.16 V
B)0.091 V
C)0.52 V
D)0.18 V
E)-0.25 V

Question 49

Using the reduction potentials given, calculate the equilibrium constant, K, at 25°C for the reaction,

A)8.5 × 10¹⁷
B)6.8
C)2.4 × 10⁴
D)1.02
E)1.2 × 10^-18

Question 50

The equilibrium constant, K_c, was found to be 2.4 × 10⁸ at 25°C for the following reaction,2X(s)+ 3Y²⁺(aq) 2X³⁺(aq)+ 3Y(s)Using this information, what is the standard reduction potential for this reaction?

A)0.25 V
B)0.083 V
C)0.17 V
D)0.50 V
E)0.21 V

Question 51

A galvanic cell is composed of these two half-cells, with the standard reduction potentials shown: The actual concentrations are: [Co²⁺(aq)] = 0.00100 M, [Cd²⁺] = 0.100 M. What is the potential of this galvanic cell? Hint: First calculate E°, then apply the solution concentrations of the galvanic cell using the Nernst equation.

A)+0.18 V
B)+0.12 V
C)+0.24 V
D)+0.060 V
E)+0.68 V

Question 52

A galvanic cell is composed of these two half-cells, with the standard reduction potentials shown: The actual concentrations in the cell are: [Co²⁺](aq)= 0.100 M, [Cd²⁺] = 0.0100 M. What is the potential of this galvanic cell?Hint: First calculate E°, then apply the solution concentrations of the galvanic cell using the Nernst equation.

A)+0.06 V
B)+0.09 V
C)+0.15 V
D)+0.18 V
E)+0.24 V

Question 53

A galvanic cell is composed of these two half-cells, with the standard reduction potentials shown: The actual concentrations in the cell are: [Co²⁺](aq)= 0.0100 M, [Cr³⁺] = 0.00100 M. What is the potential of this galvanic cell?Hint: First calculate E°, then apply the solution concentrations of the galvanic cell using the Nernst equation.

A)+0.40 V
B)+0.46 V
C)+0.52 V
D)+0.54 V
E)+1.02 V

Question 54

A galvanic cell is composed of these two half-cells, with the standard reduction potentials shown: The actual concentrations in the cell are: [Co²⁺] = 0.00100 M, [Cr³⁺]= 0.100 M. What is the potential of this galvanic cell?Hint: First calculate E°, then apply the solution concentrations of the galvanic cell using the Nernst equation.

A)+0.33 V
B)+0.39 V
C)+0.45 V
D)+0.94 V
E)+1.61 V

Question 55

A galvanic cell is composed of these two half-cells: The actual concentrations in the cell are: [Cu²⁺] = 0.00350 M, [Cr³⁺] = 0.360 M. What is the potential of this galvanic cell at 25°C?Hint: First calculate E°, then apply the solution concentrations of the galvanic cell using the Nernst equation.

A)+1.06 V
B)-0.16 V
C)+1.02 V
D)+1.14 V
E)+1.98 V

Question 56

The standard reduction potentials of Cu²⁺(aq)|Cu(s)and Ag⁺(aq)|Ag(s)are +0.34 and+0.80 V, respectively. Determine the value of the actual cell potential, E_cell, (in V)for the following cell at 25.0 °C.
Cu(s)|Cu²⁺(0.250 M)||Ag⁺(0.0010 M)|Ag(s)Hint: First calculate E°, then apply the solution concentrations of the galvanic cell using the Nernst equation.

A)+0.30 V
B)+0.14 V
C)+0.62 V
D)+0.78 V
E)+0.39 V

Question 57

Fuel cells are different from other traditional batteries because

A)they require a constant supply of reactants to produce voltage.
B)they are only used in space.
C)they have a solid medium.
D)they require voltage to work.
E)they utilize heat from combustion of gases.

Question 58

When fused (molten)sodium chloride is electrolyzed what occurs?

A)Gaseous chlorine is formed at the cathode.
B)Hydrogen gas is formed at the cathode.
C)Liquid sodium is formed at the cathode.
D)Liquid chlorine is formed at the anode.
E)Solid sodium is formed at the anode.

Question 59

In doping semiconductor materials,

A)the energy gap between the valence band and the conduction band is completely removed and a covalent bond is formed.
B)impurities are added that either provide extra electrons, or 'holes' for electrons to move through.
C)a large flow of electricity is added to the material kicking electrons out of the material and creating 'holes'.
D)the material is destroyed using an acid.
E)the material is dissolved in an organic solvent.

Question 60

When an aqueous solution of AgNO₃ is electrolyzed, a gas is formed at the anode. The gas is

A)dinitrogen tetroxide.
B)hydrogen.
C)mononitrogen monoxide.
D)nitrogen dioxide.
E)oxygen.

Question 61

Electrolysis is

A)the splitting of atomic nuclei by electrical energy.
B)the splitting of atoms by electrical energy.
C)the passage of electrical energy through a split-field armature.
D)the chemical reaction which results when electrical energy is passed through a liquid electrolyte.
E)the chemical reaction which results when electrical energy is passed through a metallic liquid.

Question 62

Which statement below is true?

A)Electrolysis cells generate alternating current when their terminals are reversed.
B)Electrolysis was discovered by Lewis Latimer.
C)Galvanic cells generate electrical energy rather than consuming it.
D)Galvanic cells were invented by Thomas Edison.
E)The Laws of Electrolysis were discovered by Alberta Nernst.

Question 63

When an aqueous solution of sodium chloride is electrolyzed, hydrogen gas is evolved at the cathode. The solution near the cathode becomes

A)acidic.
B)basic.
C)bubbly.
D)colored.
E)viscous.

Question 64

When an aqueous solution of sodium sulfate is electrolyzed, a gas is evolved at the anode. The solution near the anode becomes

A)acidic.
B)basic.
C)bubbly.
D)colored.
E)viscous.

Question 65

An electrolytic cell has two electrodes. Which statement is correct?

A)Oxidation takes place at the anode, which is positively charged.
B)Oxidation takes place at the anode, which is negatively charged.
C)Oxidation takes place at the cathode, which is positively charged.
D)Oxidation takes place at the cathode, which is negatively charged.
E)Oxidation take place at the dynode, which is uncharged.

Question 66

An electrolysis cell has two electrodes. Which statement is correct?

A)Reduction takes place at the anode, which is positively charged.
B)Reduction takes place at the anode, which is negatively charged.
C)Reduction takes place at the cathode, which is positively charged.
D)Reduction takes place at the cathode, which is negatively charged.
E)Reduction takes place at the dynode, which is uncharged.

Question 67

Which metal can be prepared by electrolysis of an aqueous solution of one of its salts?

A)aluminum
B)copper
C)magnesium
D)potassium
E)sodium

Question 68

The products of the electrolysis of molten magnesium chloride using platinum electrodes are

A)hydrogen gas and chlorine gas.
B)magnesium metal and chlorine gas.
C)magnesium metal and oxygen gas.
D)magnesium metal and hydroxide ions.
E)chlorine gas and platinum-magnesium alloy.

Question 69

The products of the electrolysis of aqueous magnesium chloride using platinum electrodes are

A)magnesium metal and chlorine gas.
B)magnesium metal and oxygen gas.
C)magnesium metal and hydroxide ions.
D)hydrogen gas and chlorine gas.
E)chlorine gas and platinum-magnesium alloy.

Question 70

When molten sodium chloride is electrolyzed, a gas is observed to form at the anode. The gas is

A)chlorine.
B)hydrogen.
C)hydrogen peroxide.
D)oxygen.
E)sodium.

Question 71

When an aqueous solution of copper sulfate is electrolyzed, a gas is observed to form at the anode. The gas is

A)hydrogen.
B)hydrogen sulfide.
C)hydrogen peroxide.
D)oxygen.
E)sulfur dioxide.

Question 72

When an aqueous solution of sodium sulfate is electrolyzed, a gas is observed to form at the anode. The gas is

A)hydrogen.
B)hydrogen sulfide.
C)hydrogen peroxide.
D)oxygen.
E)sulfur dioxide.

Question 73

When an aqueous solution of sodium sulfate is electrolyzed, a gas is observed to form at the cathode. The gas is

A)hydrogen.
B)hydrogen sulfide.
C)hydrogen peroxide.
D)oxygen.
E)sulfur dioxide.

Question 74

When an aqueous solution of magnesium sulfate is electrolyzed, what product is formed at the cathode?

A)hydrogen
B)hydrogen sulfide
C)magnesium
D)oxygen
E)sulfur dioxide

Question 75

When an aqueous solution of nickel sulfate is electrolyzed, what product is formed at the anode?

A)hydrogen
B)hydrogen sulfide
C)nickel
D)oxygen
E)sulfur dioxide

Question 76

The half-reaction that occurs at the cathode during electrolysis of aqueous sodium iodide solution is:

A)2 H₂O(l)+ 2 e^- $\rarr$ H₂(g)+ 2 OH^-(aq)
B)I₂(aq)+ 2 e^- $\rarr$ 2 I^-(aq)
C)2 I^-(aq) $\rarr$ I₂(aq)+ 2 e^-
D)Na⁺(aq)+ e^- $\rarr$ Na(s)
E)Na(s) $\rarr$ Na⁺(aq)+ e^-

Question 77

The half-reaction that occurs at the cathode during electrolysis of aqueous CuCl₂ solution is:

A)Cl₂(g)+ 2 e^- $\rarr$ 2 Cl^-(aq)
B)2 Cl(aq) $\rarr$ Cl₂(g)+ 2 e^-
C)Cu²⁺(aq)+ 2 e^- $\rarr$ Cu(s)
D)Cu⁺(aq)+ e^- $\rarr$ Cu(s)
E)2 H₂O + 2 e^- $\rarr$ H₂(g)+ 2 OH^-(aq)

Question 78

The half-reaction that should occur at the anode during electrolysis of aqueous potassium bromide solution is:

A)Br₂(g)+ 2 e^- $\rarr$ 2 Br^-(aq)
B)2 Br^-(aq) $\rarr$ Br₂(l)+ 2 e^-
C)2 H₂O $\rarr$ O₂(g)+ 4 H⁺(aq)+ 4 e^-
D)2 H⁺(aq)+ e^- $\rarr$ H₂(g)
E)Na⁺(aq)+ e^- $\rarr$ Na(s)

Question 79

The SI unit for electric current is the

A)ampere.
B)coulomb.
C)volt.
D)joule.
E)watt.

Question 80

Using the same current and similar conditions, which will require the shorter length of time?

A)Depositing 0.10 mol Ag from a Ag⁺ solution
B)Depositing 0.10 mol Cr from a Cr³⁺ solution
C)Depositing 0.10 mol Cu from a Cu²⁺ solution
D)Depositing 0.20 mol Cu from a Cu²⁺ solution
E)They should all take the same time.