Applications of Galvanic Cells and Producing Electrical Energy questions

A primary cell used in hearing aids.
Which of the following statements is NOT correct for this cell?

1. A One of the products of its reaction is a non-transition element.
2. B The oxidizing agent is a transition element.
3. C Spontaneous oxidation and reduction take place in it.
4. D The concentration of the electrolyte does not change.

In the mercury cell, all of the following are correct, except ..........

1. A No reduction of the oxygen of the cathode takes place.
2. B The electrolyte used is KOH
3. C The reaction equation: Zn + Hg²⁺ → Zn²⁺ + Hg
4. D It can store electrical energy again in the form of chemical energy.

Which of the following happens in the mercury cell when it is operating?

1. A Each zinc atom loses two electrons.
2. B Each zinc ion loses two electrons.
3. C Each mercury atom gains an electron.
4. D Each mercury ion gains an electron.

The following two reactions take place in one of the galvanic cells:
Zn(s) + 2OH⁻(aq) → ZnO(s) + H₂O(l) + 2e⁻ E° = X V
HgO(s) + H₂O(l) + 2e⁻ → Hg(l) + 2OH⁻(aq) E° = + 0.0977 V
Which of the following gives the value of (X), and what is the type of this galvanic cell?

1. A 1.1323 V / primary cell.
2. B 1.1323 V / secondary cell.
3. C 1.2523 V / primary cell.
4. D 1.2523 V / secondary cell.

From the following statements:
(1): Suitable for use in devices that work with a small voltage.
(2): The anode is made of zinc and the cathode of mercury(II) oxide.
(3): The electrolyte is a paste of KO₂ and Zn(OH)₂
(4): Anode reaction: Zn + H₂O → ZnO + 2OH⁻ + 2e⁻
Which of the following describes the mercury cell?

1. A (1), (2).
2. B (2), (3).
3. C (3), (4).
4. D (2), (4).

Which of the following graphs shows one of the properties of the dry cell?

1. A A
2. B B
3. C C
4. D D

The following graph shows what happens to the voltages of four galvanic cells with time as they discharge:
Which curve represents the mercury cell?

1. A (W).
2. B (X).
3. C (Y).
4. D (Z).

Which of the following statements describes the fuel cell?

1. A A primary cell that stores electrical energy.
2. B Its electrolyte is sulphuric acid.
3. C It produces electrical energy and water.
4. D A secondary cell supplied with external fuel.

In the fuel cell, reduction takes place for ..........

1. A H₂(g)
2. B H₂O(l)
3. C OH⁻(aq)
4. D O₂(g)

Which of the following happens in the fuel cell?

1. A OH⁻ ions move from the anode to the cathode through the electrolyte.
2. B H⁺ ions move from the anode to the cathode through the electrolyte.
3. C Electrons move from the cathode to the anode during charging.
4. D Electrons move from the cathode to the anode during discharging.

A cell that does not store energy and needs a continuous supply of fuel to work.
Which of the following describes this cell?

1. A The reaction O₂ + 2e⁻ → 2O²⁻ takes place in it.
2. B The electrolyte used in it (KOH) is anhydrous.
3. C It works at a high temperature.
4. D The fuel used in it is not suitable as a rocket-launching fuel.

A fuel cell uses 1500 L of hydrogen gas (at STP).
What is the volume and name of the other gas needed to use up all the hydrogen at the same conditions of pressure and temperature?

1. A 1500 L of oxygen gas.
2. B 1500 L of chlorine gas.
3. C 750 L of oxygen gas.
4. D 750 L of chlorine gas.

In the primary galvanic cell shown in the opposite figure:
What happens to the pH value around the two electrodes with time?

1. A The pH increases around the anode and decreases around the cathode.
2. B The pH increases around both electrodes.
3. C The pH decreases around the anode and increases around the cathode.
4. D The pH decreases around both electrodes.

The opposite figure shows the structure of the fuel cell.
Which of the following describes what happens in each of the regions (1), (2), (3), (4)?

1. A (1) oxidation of H₂, (2) movement of H⁺ ions, (3) reduction of O₂, (4) excess H₂
2. B (1) oxidation of H₂, (2) movement of electrons, (3) reduction of O₂, (4) H₂O(v)
3. C (1) oxidation of H⁺ ions, (2) movement of H⁺ ions, (3) reduction of O²⁻ ions, (4) excess H₂
4. D (1) oxidation of H⁺ ions, (2) movement of H⁺ ions, (3) reduction of O²⁻ ions, (4) H₂O(v)

When the lead-acid battery discharges ..........

1. A lead is formed.
2. B PbSO₄ is used up.
3. C sulphuric acid is used up.
4. D SO₂ gas is given off.

Which of the following represents the oxidation reaction when the lead accumulator is operating?

1. A Pb → Pb²⁺ + 2e⁻
2. B Pb²⁺ + 4e⁻ → Pb
3. C Pb²⁺ + 2e⁻ → Pb
4. D Pb → Pb⁴⁺ + 4e⁻

Using the lead accumulator for a long time leads to ..........

1. A deposition of lead(II) sulphate at the cathode and lead dioxide at the anode.
2. B an increase in the deposition of lead(II) sulphate at both the cathode and the anode.
3. C an increase in the density of the electrolyte solution.
4. D deposition of lead(II) sulphate at the anode only.

What is the mass of 250 cm³ of the electrolyte of a fully charged lead-acid battery?

1. A 250 g
2. B 300 g
3. C 325 g
4. D 340 g

In the charging reaction of the lead-acid accumulator, ..........

1. A only oxidation of lead(II) sulphate takes place.
2. B oxidation and reduction of lead(II) sulphate take place.
3. C only reduction of lead(IV) oxide takes place.
4. D oxidation and reduction of lead(IV) oxide take place.

All of the following happen when the lead accumulator discharges, except ..........

1. A Lead(II) sulphate is deposited at both the anode and the cathode.
2. B The density of the electrolyte decreases.
3. C The accumulator acts as an electrolytic cell.
4. D PbO₂ is reduced to Pb²⁺

What happens when the lead-acid battery discharges?

1. A The amount of Pb⁴⁺ ions used up is inversely proportional to the operating time.
2. B The amount of Pb²⁺ ions formed is directly proportional to the operating time.
3. C The anode acts as the positive electrode.
4. D The number of moles of H₂SO₄ formed in the electrolyte increases.

All of the following are properties of lead(II) sulphate, except that it ..........

1. A does not dissolve in water.
2. B forms at the anode when the accumulator is charged.
3. C is a white solid.
4. D has its lead oxidized and reduced when the accumulator is charged.

Which of the following substances undergo a change in oxidation number during charging and discharging of the lead accumulator?

1. A Spongy lead (✓), lead(IV) oxide (✓), sulphuric acid (✗)
2. B Spongy lead (✓), lead(IV) oxide (✓), sulphuric acid (✓)
3. C Spongy lead (✗), lead(IV) oxide (✗), sulphuric acid (✗)
4. D Spongy lead (✗), lead(IV) oxide (✗), sulphuric acid (✓)

The following statements may describe the redox reactions in the lead accumulator:
(1): Pb is oxidized to PbSO₄ in the discharging reaction.
(2): PbO₂ is reduced to PbSO₄ in the charging reaction.
(3): PbSO₄ is oxidized to PbO₂ in the charging reaction.
(4): PbSO₄ is reduced to Pb in the discharging reaction.
Which of the following gives the statements that describe the reactions taking place in the lead accumulator?

1. A (1), (2).
2. B (2), (3).
3. C (3), (4).
4. D (1), (3).

What happens to the density of the electrolyte and its pH, respectively, when the lead accumulator is charged?

1. A Increases / increases.
2. B Increases / decreases.
3. C Decreases / decreases.
4. D Decreases / increases.

A lead-acid cell has an anode oxidation potential of 0.36 V, a cathode reduction potential of 1.69 V, and the percentage of acid in the electrolyte is 38% [H₂SO₄ = 98 g/mol]
What are the density of the electrolyte and its molar concentration, respectively?

1. A 1.29 g/mL, 0.49 M
2. B 1.29 g/mL, 5 M
3. C 1 g/mL, 5 M
4. D 1 g/mL, 0.49 M

Which of the following gives the transition metals used (as metals or compounds) in making rechargeable galvanic cells?

1. A Nickel and cadmium.
2. B Nickel and cobalt.
3. C Zinc and mercury.
4. D Lead and zinc.

Which of the following gives the anode and cathode reactions in a lead-acid cell, given that the mass of one litre of the battery solution is 0.5 kg?

1. A Anode: Pb → Pb²⁺ + 2e⁻ (E° = 0.36 V), cathode: Pb⁴⁺ + 2e⁻ → Pb²⁺ (E° = 1.69 V)
2. B Anode: Pb → Pb²⁺ + 2e⁻ (E° = 0.36 V), cathode: Pb⁴⁺ + 2e⁻ → Pb²⁺ (E° = 1.39 V)
3. C Anode: Pb → Pb²⁺ + 2e⁻ (E° = 0.26 V), cathode: Pb⁴⁺ + 2e⁻ → Pb²⁺ (E° = 1.69 V)
4. D Anode: Pb → Pb²⁺ + 2e⁻ (E° = 0.26 V), cathode: Pb⁴⁺ + 2e⁻ → Pb²⁺ (E° = 1.39 V)

All of the following are properties of the lithium-ion battery, except that it ..........

1. A contains an anhydrous electrolyte.
2. B stores a large amount of energy relative to its size.
3. C works at high temperatures.
4. D is a dry secondary cell.

The following two reactions represent the discharging of a (silver–zinc) cell:
Zn(s) + 2OH⁻(aq) → ZnO(s) + H₂O(l) + 2e⁻
Ag₂O(s) + H₂O(l) + 2e⁻ → 2Ag(s) + 2OH⁻(aq)
Which of the following gives the substances used up during discharging of the cell and the equation of the overall reaction?

1. A Substances used up: Ag₂O, Zn / Equation: Zn(s) + 2OH⁻(aq) + Ag₂O(s) → ZnO(s) + 2Ag(s) + 2OH⁻(aq)
2. B Substances used up: Ag₂O, Zn / Equation: Zn(s) + Ag₂O(s) → 2Ag(s) + ZnO(s)
3. C Substances used up: Zn only / Equation: Zn(s) + Ag₂O(s) → 2Ag(s) + ZnO(s)
4. D Substances used up: Zn only / Equation: Zn(s) + 2OH⁻(aq) + Ag₂O(s) → ZnO(s) + 2Ag(s) + 2OH⁻(aq)

What change happens to the ion of the transition element while the lithium-ion battery is being charged?

1. A Oxidation, and the number of unpaired electrons increases.
2. B Oxidation, and the number of unpaired electrons decreases.
3. C Reduction, and the number of paired electrons increases.
4. D Reduction, and the number of paired electrons decreases.

Which of the following describes the movement of lithium ions and the movement of electrons in the lithium-ion battery?

1. A Lithium ions move in the same direction as the electrons during charging.
2. B Lithium ions move in the opposite direction to the electrons during charging.
3. C Lithium ions move in the opposite direction to the electrons during discharging.
4. D The movement of lithium ions is not related to the movement of electrons during discharging.

From the following assumption and its explanation:
Assumption: There is a thin insulator between the anode and the cathode.
Explanation: To allow lithium ions to move from the negative electrode to the positive electrode during discharging.
Which of the following describes the lithium-ion battery?

1. A Assumption (✓), explanation (✓)
2. B Assumption (✓), explanation (✗)
3. C Assumption (✗), explanation (✓)
4. D Assumption (✗), explanation (✗)

The anode material is the same in ..........

1. A the fuel cell and the mercury cell.
2. B the lithium-ion battery and the lead-acid battery.
3. C the Daniell cell and the mercury cell.
4. D the fuel cell and the lead-acid battery.

Which of the following describes the type of reactions taking place in the fuel cell and in the lithium-ion cell?

1. A Fuel cell: spontaneous only, lithium-ion cell: spontaneous only
2. B Fuel cell: spontaneous and non-spontaneous, lithium-ion cell: spontaneous and non-spontaneous
3. C Fuel cell: spontaneous only, lithium-ion cell: spontaneous and non-spontaneous
4. D Fuel cell: spontaneous and non-spontaneous, lithium-ion cell: spontaneous only

The galvanic cells in which the pH value of the electrolyte is greater than 7 are ..........

1. A the mercury cell and the lithium-ion battery.
2. B the mercury cell and the fuel cell.
3. C the fuel cell and the lithium-ion battery.
4. D the lithium-ion battery and the lead accumulator.

The opposite figure represents a lithium-ion battery.
Does the figure show charging or discharging, and what role does electrode (X) play in this case?

1. A The battery is charging, electrode (X) acts as the cathode
2. B The battery is discharging, electrode (X) acts as the anode
3. C The battery is charging, electrode (X) acts as the anode
4. D The battery is discharging, electrode (X) acts as the cathode

The opposite figure represents a fuel cell and a lithium-ion battery during discharging.
Which of the following is correct?

1. A (1): cathode, (3): anode.
2. B (3): anode, (4): cathode.
3. C (2): anode, (4): cathode.
4. D (2): anode, (3): cathode.

The mercury cell is one of the primary cells:
(1) Why is the mercury cell described as an alkaline cell?
(2) Why is the zinc used in the anode of this cell in the form of a powder?

From the opposite figure, write the reaction that takes place at:
(1) electrode (X) when the battery discharges.
(2) electrode (Y) when the battery is recharged.

The following figure shows one of the reactions that take place in the lead accumulator:
(1) Write the symbolic equation of the reaction that takes place.
(2) Does this reaction take place at the cathode or the anode? Explain.

75 mL of 0.2 M sodium hydroxide solution was used to titrate a 1.5 mL sample of the electrolyte of a charged lead accumulator:
(1) Calculate the concentration of this electrolyte.
(2) Is the concentration of the electrolyte greater in the charged or in the uncharged accumulator? Explain.

Explain, writing the equation of the reaction, the type of ions that are:
(1) produced at the cathode in the fuel cell.
(2) used up at the cathode in the lead accumulator.

Lithium ions move through the electrolyte of a lithium-ion battery towards the positive electrode in case (X), and their path is reversed in case (Y):
(1) Write the symbolic equation of the reaction that takes place in case (X).
(2) Does case (Y) represent charging or discharging? Explain.

The opposite figure shows the structure of a lithium-ion battery:
(1) Does device (X) represent a mobile phone or a source of electric current? Explain.
(2) Write the equation of the reaction that takes place in this case.

The following reaction takes place in a galvanic half-cell: Xⁿ⁺ + ne⁻ → X
Which of the following gives element (X) and the use of this cell?

1. A Element: Hg, use: hearing aids
2. B Element: Pb, use: medical devices
3. C Element: H₂, use: obtaining drinking water for astronauts
4. D Element: O₂, use: spacecraft

Which of the following is correct during the discharging of a lithium-ion cell?

1. A Lithium ions move from the positive electrode to the negative electrode.
2. B Electrons move from the positive electrode to the negative electrode.
3. C Lithium ions move to the negative electrode.
4. D Lithium ions move to the positive electrode.

Cell (R) is made of the two electrodes (X) and (Y), where:
E°(X³⁺/X) = –1.670 V
E°(Y²⁺/Y) = +0.34 V
Which of the following gives the number of cells (R) that must be connected in series to obtain a battery with an emf of 8.05 V, and the role of each electrode in the cell?

1. A 4 cells, with (Y) as the anode and (X) as the cathode.
2. B 6 cells, with (Y) as the anode and (X) as the cathode.
3. C 4 cells, with (X) as the anode and (Y) as the cathode.
4. D 6 cells, with (X) as the anode and (Y) as the cathode.

Which of the following processes represents a redox reaction that can be used to obtain electrical energy?

1. A Conversion of lead sulphate into lead(IV) ions in the car battery.
2. B Electroplating some car parts with chromium metal to protect them from rusting.
3. C Electrolysis of water into hydrogen and oxygen.
4. D Combination of hydrogen with oxygen to form water.

Which of the following happens in the lead-acid battery during charging?

1. A Pb²⁺ ions change into Pb⁴⁺ ions at the cathode.
2. B Pb²⁺ ions change into Pb at the anode.
3. C Electrons move from the negative electrode to the positive electrode.
4. D Electrons move from the anode to the cathode.

Which of the following is correct for the negative hydroxide ions in the fuel cell?

1. A They are used up by the reduction reaction and formed by the oxidation reaction.
2. B They are used up by the oxidation reaction and formed by the reduction reaction.
3. C Their concentration decreases at the cathode.
4. D Their concentration increases at the anode.

Which of the following is correct for both the fuel cell and the mercury cell?

1. A Both are cells that convert the chemical energy stored in them into electrical energy.
2. B Reduction takes place in each of them at the negative electrode.
3. C The components of both cells are used up during operation.
4. D Both are alkaline cells and the concentration of the electrolyte does not change during operation.

When the lead accumulator discharges.
Which of the following happens as a result?

1. A The mass of the anode decreases and the mass of the cathode increases.
2. B The density of the solution increases and lead(II) ions form at the anode.
3. C The density of the solution decreases and the mass of the anode increases.
4. D The density of the solution increases and lead(II) ions form at the cathode.

A car battery (X), with an acid density of 1.19 g/cm³, is connected in parallel to another car battery (Y), with an acid density of 1.29 g/cm³.
Which of the following happens in this case?

1. A Pb²⁺ ions are oxidized to Pb⁴⁺ ions at the positive electrode of battery (X), and lead atoms are oxidized to Pb²⁺ ions at the positive electrode of battery (Y).
2. B Pb²⁺ ions are reduced to Pb atoms at the positive electrode of battery (X), and Pb²⁺ ions are reduced to Pb atoms at the positive electrode of battery (Y).
3. C Pb²⁺ ions are oxidized to Pb⁴⁺ ions at the negative electrode of battery (X), and lead atoms are oxidized to Pb²⁺ ions at the positive electrode of battery (Y).
4. D Pb²⁺ ions are reduced to Pb atoms at the negative electrode of battery (X), and Pb⁴⁺ ions are reduced to Pb²⁺ ions at the positive electrode of battery (Y).

Which of the following choices describes what happens to the hydrogen of the hydroxyl group while the fuel cell is operating?

1. A It is oxidized and loses 4 electrons.
2. B It is oxidized and loses an electron.
3. C It is reduced and gains 4 electrons.
4. D It is neither oxidized nor reduced.

What happens when the two electrodes of the lithium battery are connected to an external electrical source with a slightly higher voltage?

1. A The (Li⁺) ion gains an electron at the cathode.
2. B The lithium atom loses an electron at the cathode.
3. C The (Li⁺) ion gains an electron at the anode.
4. D The lithium atom gains an electron at the anode.

In the mercury cell, when the zinc container is replaced by a nickel container under standard conditions,
which of the following is correct, given that mercury comes after hydrogen in the electrochemical series?

1. A The emf value decreases
2. B The emf value increases
3. C Nickel acts as the cathode.
4. D The direction of the current in the wire changes.

In the two opposite cells:
(1) Y + X⁺ → Y⁺ + X, emf = 0.4 V
(2) W + Z⁺ → W⁺ + Z, emf = 0.9 V
When the like electrodes of cells (1) and (2) are connected together in parallel.
Which of the following answers is correct?

1. A Cell (1) is galvanic, cell (2) is electrolytic, electrode (Y) is the anode.
2. B Cell (1) is galvanic, cell (2) is electrolytic, electrode (Z) is the cathode.
3. C Cell (2) is galvanic, cell (1) is electrolytic, electrode (W) is the anode
4. D Cell (2) is galvanic, cell (1) is electrolytic, electrode (Z) is the anode

The reaction that takes place at the anode of a primary galvanic cell is ..........

1. A Ag₂O(s) + Zn(s) → ZnO(s) + 2Ag(s)
2. B Zn(s) + 2OH⁻(aq) → ZnO(s) + H₂O(l) + 2e⁻
3. C Ag₂O(s) + H₂O(l) + 2e⁻ → 2Ag(s) + 2OH⁻(aq)
4. D ZnO(s) + H₂O(l) + 2e⁻ → Zn(s) + 2OH⁻(aq)

Which of the following describes the electrical cell that uses the same gaseous fuel as that used in launching rockets?

1. A The reactions inside the cell cannot be controlled.
2. B It does not store any of the energy produced.
3. C It works at a low temperature.
4. D It does not need a continuous supply of gaseous fuel to work.

The redox reactions in the fuel cell lead to ..........

1. A movement of hydroxide ions towards the anode.
2. B movement of hydroxide ions towards the cathode.
3. C conversion of oxygen into hydroxide ions by oxidation.
4. D conversion of hydrogen by reduction into water molecules.

While the fuel cell is operating.
Which of the following choices is correct?

1. A The concentration of the electrolyte stays constant.
2. B The concentration of the electrolyte decreases.
3. C The pH value of the electrolyte decreases.
4. D The pH value of the electrolyte increases.

Which of the following is correct when the lead-acid battery discharges?

1. A The concentration of the acid increases and its density decreases.
2. B The concentration of the acid decreases and its density increases.
3. C The oxidation number of the cathode material changes from (+4) to (+2).
4. D The oxidation number of the anode material changes from (0) to (+4).

In the car battery, the electrode at which the reaction: PbSO₄ → Pb⁴⁺ + 2e⁻ + SO₄²⁻ takes place is ..........

1. A the cathode, during discharging.
2. B the cathode, during charging.
3. C the anode, during discharging.
4. D the anode, during charging.

Which of the following choices is correct while a lead accumulator is being charged?

1. A The concentration of the electrolyte decreases and lead forms at the anode.
2. B The concentration of the electrolyte increases and lead(II) oxide forms at the cathode.
3. C The concentration of the electrolyte increases and lead forms at the cathode.
4. D The concentration of the electrolyte does not change and lead(IV) oxide forms at the anode.

When the lead accumulator is charged, all of the following happen, except ..........

1. A The concentration of the acid increases.
2. B The mass of water decreases.
3. C The pOH value decreases.
4. D The pH value decreases.

While a car battery is being charged ..........

1. A the emf value of the car battery decreases and the concentration of the acid increases.
2. B the emf value of the car battery increases and the concentration of the acid decreases.
3. C the negative terminal of the external source is connected to the lead electrode.
4. D the positive terminal of the external source is connected to the lead electrode.

When the lead accumulator is connected to an external electric source with an emf of 14 V,
which of the following is correct?

1. A The pOH value of the electrolyte solution decreases.
2. B The pH value of the electrolyte solution decreases.
3. C The oxidation number of lead at the anode increases.
4. D The amount of water in the battery increases.

In a lead-acid battery, the following data were recorded during discharging:
• Anode potential = +0.36 V
• Cathode potential = +1.69 V
• Hydrometer reading = 1 g/cm³
So this battery ..........

1. A is fully charged, and the battery produces 12 V
2. B needs recharging, and the battery produces 2.05 V after charging.
3. C is fully charged, and the cell produces 12 V
4. D needs recharging, and the cell produces 2.05 V after charging.

In the lithium-ion battery, lithium ions move through (LiPF₆) ..........

1. A from the negative anode to the positive cathode during discharging.
2. B from the negative anode to the positive cathode during charging.
3. C from the cathode to the anode during discharging.
4. D from the cathode to the anode during charging.

Comparing the reducing agent in the mercury cell and in the fuel cell,
which of the following is the stronger?

1. A H₂
2. B H⁺
3. C Zn²⁺
4. D Zn

In the mercury cell and the fuel cell, which of the following is correct?

1. A Oxygen ions in the mercury cell are oxidized.
2. B Oxygen ions in the fuel cell are reduced.
3. C Oxygen ions in the mercury cell are neither oxidized nor reduced.
4. D Oxygen ions in the fuel cell are oxidized.

Given that the electrode potentials of a secondary galvanic battery are as follows:
NiO₂ + 2H₂O + 2e⁻ → Ni(OH)₂ + 2OH⁻ E° = + 0.49 V
Fe(OH)₂ + 2e⁻ → Fe + 2OH⁻ E° = – 0.88 V
To fully charge this battery, it is connected to an electrical source with an emf of ..........

1. A 2 V
2. B 1.37 V
3. C 220 V
4. D 1.3 V

Study the following figure:
(1) Identify the anode and the cathode in the lithium battery.
(2) State which one (the lead battery or the lithium cell) has spontaneous reactions taking place in it.