Free Printable Electrode Potentials Practice

Worksheets

Electrode Potentials Practice

Total questions: 48

Worksheet time: 2hrs 42mins

Name

Class

Date

In a Galvanic Cell, the anode is...

positive

negative

In a Galvanic Cell, the cathode is...

positive

negative

Oxidation occurs at the...

anode

cathode

Reduction occurs at the...

anode

cathode

In a Galvanic cell, the electrons flow from the...

anode to the cathode

cathode to the anode

E_cell =

E_red - E_ox

E_red + E_ox

E_ox - E_red

E_ox + E_red

In the list of standard electrode potentials, the strongest reducing agent is...

Li⁺

F₂

F^-

In the list of standard electrode potentials, the strongest oxidising agent is...

Li⁺

F₂

F^-

In a redox reaction, the oxidising agent... (choose two options)

is oxidised

is reduced

increases its oxidation number

decreases its oxidation number

10.

In a redox reaction, the reducing agent... (choose two options)

is oxidised

is reduced

increases its oxidation number

decreases its oxidation number

11.

In a Galvanic cell, the cations in the salt bridge...

flow the same way as the electrons flow in the wire

flow the opposite way to the electron flow in the wire

stay in the salt bridge

12.

In a Galvanic Cell, the salt bridge...

completes the circuit so that electrons can flow through the wire

maintains charge balance

is soaked in an unreactive electrolyte such as KNO₃

all of the above

13.

In the above Galvanic Cell, which half cell is undergoing reduction?

Cu | Cu²⁺

Zn | Zn²⁺

14.

In any Galvanic Cell, which half cell will undergo reduction?

The half cell with the lower standard electrode potential

The half cell with the higher standard electrode potential

15.

If an electrochemical reaction is spontaneous, what will E_cell be?

positive

negative

16.

Consider the galvanic cell reaction Zn (s) + Cu²⁺ (aq) → Cu (s) + Zn²⁺ (aq) When the cell is running spontaneously, which is the only true statement?

The copper electrode loses mass and the zinc electrode is the cathode.

The copper electrode gains mass and the copper electrode is the cathode.

The zinc electrode gains mass and the zinc electrode is the anode.

The zinc electrode loses mass and the zinc electrode is the cathode.

17.

A certain galvanic cell has for its spontaneous cell reaction: Zn + HgO → ZnO + Hg

Which is the half-reaction occurring at the anode?

HgO + 2 e- → Hg + O^2-

Zn²⁺ + 2 e- → Zn

Zn → Zn²⁺ + 2 e-

ZnO + 2 e- → Zn

18.

What is the standard electrode which all other standard electrode potentials are measured against?

helium

hydrogen

magnesium

potassium

19.

A galvanic cell was set up using the Cu²⁺/Cu and Fe³⁺/Fe half-cells. The standard redox potentials for these half-cells are:
Cu²⁺(aq) + 2e^- → Cu(s); E⁰ = 0.34 V
Fe³⁺(aq) + e^- → Fe²⁺(aq); E⁰ = 0.77 V
The oxidant and reductant reacting in this galvanic cell are, respectively:

Fe³⁺; Cu

Fe²⁺; Cu

Cu²⁺; Fe³⁺

Cu²⁺; Fe²⁺

20.

A galvanic cell was set up from a Cl₂/Cl^- half-cell and a standard hydrogen electrode (SHE). It was found that the voltmeter reading was 1.36 V and the chlorine half-cell was the positively-charged electrode. Which statement about this galvanic cell is INCORRECT?

Both of the electrodes should be made of platinum.

The chlorine half-cell is the anode.

As the cell operates, the pH of the solution in the SHE decreases.

The standard redox potential for the chlorine half-cell must be +1.36 V.

21.

The net cell reaction in a particular galvanic cell is:
Cu²⁺(aq) + Sn²⁺(aq) → Cu(s) + Sn⁴⁺(aq)
In this cell, we would expect to observe:

crystals of copper forming on the anode.

the cathode corroding away.

the solution in the copper half-cell becoming lighter in colour.

the voltmeter needle showing that the copper electrode has negative polarity.

22.

A galvanic cell was set up as shown.
The standard redox potentials for these half-cells are:
Ag⁺(aq) + e^- → Ag(s); E⁰ = 0.89 V
Ni²⁺(aq) + 2e^- → Ni(s); E⁰ = -0.23 V
In this cell:

the silver electrode has positive polarity and the nickel electrode will corrode.

the silver electrode has positive polarity and the silver electrode will corrode.

the silver electrode has negative polarity and the nickel electrode will corrode.

the silver electrode has negative polarity and the silver electrode will corrode.

23.

In the ethanol fuel cell, ethanol is pumped in at one electrode and oxygen is pumped in at the other. The only products of the cell reaction are the same as those that would be produced if ethanol was burnt directly in excess air. What is the correct equation for the reaction at the anode, if an acidic electrolyte is used?

O₂(g) + 4H⁺(aq) + 4e^-→ 2H₂O(l)

O₂(g)+ 2H⁺(aq) + 2e^- → 2H₂O₂(aq)

C₂H₅OH(aq) + 3H₂O(l) → 2CO₂(g) + 12H⁺(aq) + 12e^-

C₂H₅OH(aq) + 3H₂O(l) → 2CO₂(g) + 11H⁺(aq) + 11e^-

24.

The diagram below shows a hydrogen–oxygen fuel cell that is operating with an acidic electrolyte.
What is Gas X and what is the polarity of electrode N?

Hydrogen; positive

Hydrogen; negative

Oxygen; positive

Oxygen; negative

25.

A galvanic cell was set up using the Pb⁴⁺/Pb²⁺ and Pb²⁺/Pb half-cells. The standard redox potentials for these half-cells are:
Pb⁴⁺(aq) + 2e^- → Pb²⁺(aq); E⁰ = 1.69 V
Pb²⁺(aq) + e^- → Pb(s); E⁰ = -0.13 V
What metal should be used for the electrode for the Pb⁴⁺/Pb²⁺ half-cell and what would be the potential difference across the cell?

Lead; 1.56 V

Lead; 1.82 V

Platinum; 1.56 V

Platinum; 1.82 V

26.

In a methane–oxygen fuel cell, the net cell reaction is:
CH₄(g) + O₂(g) → CO₂(g) + 2H₂O(l)
If an alkaline electrolyte is used, the equation for the reaction at the positive electrode is:

O₂(g) + 2H₂O(l) + 4e^-→ 4OH^-(aq)

O₂(g) + 4H⁺(aq) + 4e^-→ 2H₂O(l)

CH₄(g) + 2H₂O(l) →CO₂(g) + 8H⁺(aq) + 8e^-

CH₄(g) + 8OH^-(aq) →CO₂(g) + 6H₂O(l) + 8e^-

27.

he standard redox potentials for a number of substances are shown below:
F₂(g) + 2e^-→ 2F^-(aq); E⁰ = 2.87 V
O₂(g)+ 4H⁺(aq)+ 4e^-→ 2H₂O(l); E⁰ = 1.23 V
Cu²⁺(aq) + 2e^-→ Cu(s); E⁰ = 0.34 V
Fe²⁺(aq) + e^-→ Fe(s); E⁰ = -0.41V
2H₂O(l) + 2e^-→ H₂(g) + 2OH^-(aq); E⁰ = -0.83 V
Mg²⁺(aq) + 2e^-→ Mg(s); E⁰ = -2.38 V
If all of these substances were available, what galvanic cell could be set up using these substances that would steadily deliver approximately 1.6 V?

F₂/F^- and O₂/H₂O

O₂/H₂O and Fe²⁺/Fe

O₂/H₂O and Cu²⁺/Cu

H₂O/H₂ and Mg²⁺/Mg

28.

When the current is flowing in a primary galvanic cell (such as the alkaline cell used in a torch):

electrons travel through the porous barrier that separates the two half-cells.

the electrode marked with a (+) sign is the anode.

a reduction reaction occurs at the negative electrode.

the anode starts to corrode.

29.

The cell reaction occurring in a particular button cell was:
Zn(s) + Ag₂O(s) + H₂O(l) → 2Ag(s)+ Zn(OH)₂(s)
This cell delivered 1.50 V. The half-equation for the silver half-cell is:
Ag₂O(s)+ H₂O(l)+ 2e^-→ 2Ag(s)+ 2OH^-(aq); E⁰ = 0.34 V
The standard redox potential for the zinc half-cell must be:

-1.16 V

+1.16 V

-1.84 V

+1.84 V

30.

What is the key difference between a galvanic cell and a fuel cell?

Galvanic cells deliver direct current; fuel cells deliver alternating current.

Galvanic cells are essentially for energy storage; fuel cells work continuously.

Galvanic cells do not use gases as reactants; fuel cells only use gases.

Galvanic cells are not rechargeable; fuel cells are constantly recharged.

31.

In commercial galvanic cells, a separator is used instead of a salt bridge. Which of the following is NOT a property that the separator should possess?

Good conductor of electricity

Will allow certain ions to migrate through it

Inert

Low density

32.

Consider the galvanic cell given.
Which of the following deductions about this cell is correct?

Oxidation is occurring in half-cell 2

The positive electrode is in half-cell 2

Oxidation is occurring in half-cell 1

The negative electrode is in half-cell 1

33.

Consider the galvanic cell represented, operating at 25^oC , 101.3 kPa and using 1 M solutions.
The product(s) of the half-reaction occurring in half-cell 1 is (are)

Ni (s)

Ni²⁺ (aq)

H₂O₂ (aq)/H⁺ (aq)

H₂O (l)

34.

A galvanic cell is established to power a torch, as shown.
For this cell, the

electrons will flow from the aluminium to the hydrogen half-cell

aluminium electrode will be the positive anode

concentration of aluminium ions in solution will be falling

hydrogen half-cell will be the negative cathode

35.

A galvanic cell is established to power a torch, as shown.
For this cell, the overall equation will be

2Al(s)+3H_2(g)→2Al³⁺(aq)+6H⁺(aq)

3Cl^-(aq)+Al(s)→AlCl₃(aq)

2Al³⁺(aq)+3H_2(g)→2Al(s)+6H⁺(aq)

2Al(s)+6H⁺(aq)→2Al³⁺(aq)+3H₂(g)

36.

A VCE chemistry student sets up a galvanic cell using two standard half-cells with half reactions.
Half-cell 1: Cr³⁺(aq)+e^-→Cr²⁺(aq)
Half-cell 2: Cr(s)→Cr²⁺(aq)+2e^-Sutable materials for the electrodes of te two half-cells are

Half-cell 1: Platinum; Half-cell 2: Platinum

Half-cell 1: Platinum; Half-cell 2: Chromium

Half-cell 1: Chromium; Half-cell 2: Chromium

Half-cell 1: Chromium; Half-cell 2: Platinum

37.

The experimental arrangement shows a:
- silver rod dipping into a 1.0 M solution of AgNO₃ (aq)
- nickel rod dipping into a 1.0 M solution of Ni(NO₃)₂(aq)
The solutions are connected to each other with a salt bridge consisting of an inverted U-tube containing ammonium nitrate solution.
Which of the following alternatives correctly describes the polarity of, and the reaction that occurs at, the anode of this cell?

Negative; Ag⁺(aq)+e^-→Ag(s)

Negative; Ni(s)→Ni²⁺(aq)+2e^-

Positive; Ag⁺(aq)+e^-→Ag(s)

Positive; Ni(s)→Ni²⁺(aq)+2e^-

38.

A galvanic cell consists of one half-cell that is made up of an inert graphite electrode in a solution containing 1.0 M Fe²⁺ (aq) and 1.0 M Fe³⁺ (aq) at 25^oC. Which one of the following could be used as the second half-cell so that the polarity of the electrode in this second half-cell is positive?

a lead electrode in a solution of 1.0 M Pb²⁺ (aq)

a silver electrode in a solution of 1.0 M Ag⁺ (aq)

an iron electrode in a solution of 1.0 M Fe²⁺ (aq)

an inert graphite electrode in a solution of 1.0 M Br^- (aq)

39.

Two standard galvanic cells are shown.
On the basis of the polarity of the electrodes shown, which one of the following reactions would NOT be expected to occur spontaneously?

Co²⁺(aq)+Cd(s)→Co(s)+Cd²⁺(aq)

2Mn³⁺(aq)+Co(s)→2Mn²⁺(aq)+Co²⁺(aq)

2Mn³⁺(aq)+Cd(s)→2Mn²⁺(aq)+Cd²⁺(aq)

2Mn²⁺(aq)+Co²⁺(aq)→2Mn³⁺(aq)+Co(s)

40.

AlF₆ ^3– + 3 e^– → Al + 6 F^{– 1}

Which of the following occurs in the reaction?

AlF₆^3– is reduced at the cathode.

Al is oxidized at the anode.

Aluminum is converted from the –3 oxidation state to the 0 oxidation state.

41.

Which of the following statements applies to the change in mass of the electrodes involved in this electrochemical cell?

Electrode A is the anode and it gains mass

since metal ions are being converted to metal

atoms which often adhere to the electrode.

Electrode B is the anode and it gains mass

since metal ions are being converted to metal

atoms which often adhere to the electrode.

Electrode A is the cathode and it gains mass since metal ions are being converted to metal atoms which often adhere to the electrode.

Electrode B is the cathode and it gains mass since metal ions are

being converted to metal atoms which often adhere to the electrode.

42.

A student wishes to construct a thermodynamically favorable galvanic cell using electrodes made of chromium and silver. Each half cell will consist of the electrode partially submerged in a 1.0 M solutions of its nitrate salt. The two electrodes will be connected by separate wires to a voltmeter and the two half-cells will be connected with a salt bridge.

The student constructs another galvanic cell still using

silver and chromium electrodes, but substitutes a 0.50 M

solution of silver nitrate for the 1.0 M solution of silver

nitrate in the silver half-cell. Which of the following best

describes the effect this substitution has on the initial reading on the voltmeter?

The voltage will increase in both cells.

The voltage will decrease in both cells.

The voltage will increase due to fewer reactants being present.

The voltage will decrease due to fewer reactants being present.

43.

Which of the following occurs if a 50-milliliter sample of a 2-molar Cd(NO₃)₂ solution is added to the left beaker?

Voltage increases.

Voltage decreases.

Voltage becomes zero and remains at zero.

No change in voltage occurs.

44.

An iron nail is put into a solution of copper nitrate, iron is above copper in the activity series of metals, what will happen?

iron will be reduced

bubbles of oxygen gas will form on iron nail

the iron nail will become copper plated

no reaction occurs

45.

What occurs to the mass of copper electrode in the following reaction?

Zn/Zn²⁺ // Cu²⁺/Cu

increases

decreases

remains the same

46.

Which metal is the negative electrode?

Zn/Zn²⁺ // Cu²⁺/Cu

zinc

copper

47.

What reaction occurs at the anode?

Ag⁺/Ag = 0.80V

Ni²⁺/Ni = -0.25V

Ag⁺ + e^- →Ag

Ag → Ag⁺ + e^-

Ni²⁺ + 2e^- → Ni

Ni → Ni²⁺ + 2e^-

48.

What would be the theoretical cell potential of the previous electrochemical cell?

Ag⁺/Ag = 0.80V

Ni²⁺/Ni = -0.25V

1.05V

-1.05V

0.55V

-0.55V

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Electrode Potentials Practice

Total questions: 48

Worksheet time: 2hrs 42mins

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