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WorksheetsIGCSE CHEMISTRY: ELECTROCHEMISTRY
Total questions: 60
Worksheet time: 33mins
What is a redox reaction?
A reaction where both reactants get reduced.
A reaction where both reactants get oxidized.
A reaction that involves a transfer of electrons between reactants.
A reaction that involves the combustion of at least one reactant.
What is reduction?
It is the gain of electrons.
It is the loss of electrons.
It is the creation of electrons.
It is the destruction of electrons.
What is oxidation?
It is the gain of electrons.
It is the loss of electrons.
It is the creation of electrons.
It is the destruction of electrons.
What is a reducing agent?
It is the species that gets reduced -- gains electrons.
It is the species that gets oxidized -- loses electrons.
It is the species that creates electrons.
It is the species that destroys electrons.
What is an oxidizing agent?
It is the species that gets reduced -- gains electrons.
It is the species that gets oxidized -- loses electrons.
It is the species that creates electrons.
It is the species that loses electrons.
What is a half-reaction?
It is a reaction at equilibrium where half of the substances are reactants and half of the substances are products.
It is the reaction that occurs when the switch of a galvanic cell is open.
It shows EITHER the reduction component or the oxidation component of a redox reaction.
It shows BOTH the reduction and oxidation components of a redox reaction.
What is an anode?
It is the electrode where oxidation takes place.
It is the electrode where reduction takes place.
It is an aqueous solution containing an electrode.
It is the salt bridge that connects half-cells.
What is a cathode?
It is the electrode where oxidation takes place.
It is the electrode where reduction takes place.
It is an aqueous solution containing an electrode.
It is the salt bridge that connects half-cells.
An oxidizing agent will
increase in mass
lose electrons
be reduced
increase in oxidation number
In a redox reaction, the species that loses electrons
is called the cathode
is oxidized
gains mass at the electrode
decreases in oxidation number
The reaction 2NaCl → 2Na + Cl2 is an example of
a reduction reaction, only
both an oxidation and reduction reaction
an oxidation reaction, only
neither an oxidation nor a reduction reaction
Oxidation-reduction reactions occur because of the competition between particles for
electrons
positrons
protons
neutrons
Mg + PbCl2 → MgCl2 + Pb
Which statement correctly describes the oxidation and reduction that occur?
Mg is oxidized and Pb+2 is reduced
Mg is oxidized and Cl- is reduced
Mg is reduced and Cl- is oxidized
Mg is reduced and Pb+2 is oxidized
In the reactions
Sn+2 + 2Fe+3 --> Sn+4 + 2Fe+2,
the reducing agent is
Fe+3
Sn+2
Sn+4
Fe+2
Pb + 2Ag+ → Pb+2 + 2Ag
The chemical species being reduced is
Ag
Pb
Pb+2
Ag+
In the reactions
Sn+2 + 2Fe+3 → Sn+4 + 2Fe+2
the oxidizing agent is
Sn+4
Sn+2
Fe+3
Fe+2
If acidified potassium dichromate(VI) (K2Cr2O7) acts as oxidizing agent, color changes from
orange to red
orange to green
yellow to green
yellow to red
In electrolysis of copper purification, at cathode
pure copper gets deposited
the object to be electroplated is kept
impure copper gets deposited
CuSO4 gets deposited
An electrolytic cell uses electrical energy to drive
chemical reaction
physical reaction
no reaction
none of above
When water is electrolyzed, gas collected at cathode, is
sulphur
oxygen
hydrogen
sulphur dioxide
In electrolysis, particles which move towards cathode are called
anions
cations
photons
positrons
The diagram shows a failed attempt to copper-plate a pan.
Which action will plate the pan with copper?
cooling the copper sulfate solution in an ice bath
heating the copper sulfate solution to boiling point
increasing the voltage from 3V to 6V
making the pan the cathode and the copper the anode
The diagram shows the electroplating of a steel object.
A student made the following statements.
1. The object turns a reddish-brown colour.
2. The copper sulfate solution changes to a paler blue colour.
3. The copper electrode becomes smaller.
Which statements are correct?
1, 2 and 3
1 and 2 only
1 and 3 only
2 and 3 only
Which metal could not be used for electroplating by using an aqueous solution?
chromium
copper
silver
sodium
Which products are formed at the anode and cathode when electricity is passed through molten
lead(II) bromide?
A
B
C
D
The diagram shows an electrical cable.
Which statement about the substances used is correct?
The coating is plastic because it conducts electricity well.
The core is copper because it conducts electricity well.
The core is copper because it is cheap and strong.
The core is iron because it is cheap and strong.
The diagram shows apparatus used in an attempt to electroplate a metal ring with copper.
The experiment did not work.
What change is needed in the experiment to make it work?
Add solid copper(II) sulfate to the electrolyte.
Increase the temperature of the electrolyte.
Replace the copper electrode by a carbon electrode.
Reverse the connections to the battery.
Substance X was electrolysed in an electrolytic cell.
A coloured gas was formed at the anode and a metal was formed at the cathode.
What is substance X?
aqueous sodium chloride
molten lead bromide
molten zinc oxide
solid sodium chloride
The diagram shows apparatus for plating a spoon with silver.
Which statement is not correct?
Silver would stick to the spoon because it is a very reactive metal.
The metal electrode would be made from silver.
The spoon would be connected to the negative of the power supply.
The electrolyte would be a silver salt dissolved in water.
Three electrolysis cells are set up. Each cell has inert electrodes.
The electrolytes are listed below.
Cell 1 - aqueous sodium chloride
Cell 2 - concentrated hydrochloric acid
Cell 3 - molten lead(II) bromide
In which cells is a gas formed at both electrodes?
1 and 2
1 and 3
2 only
3 only
The diagram shows how aluminium is manufactured by electrolysis.
What are the anode and cathode made of?
anode - aluminium / cathode - aluminium
anode - aluminium / cathode - graphite
anode - graphite / cathode - aluminium
anode - graphite / cathode - graphite
Which statement about electroplating iron with chromium is correct?
A catalyst is used.
The anode is chromium.
The electrolyte contains aqueous iron ions.
The electrolyte contains solid chromium ions.
Which statement describes what happens during electrolysis?
Covalent compounds produce more complex substances.
Covalent compounds produce simpler substances.
Ionic compounds produce more complex substances.
Ionic compounds produce simpler substances.
Aqueous copper (II) sulfate is electrolysed using carbon electrodes.
What is produced at each electrode?
A
B
C
D
Diagram shows an electrolysis cell.
Which of the substances cause the bulb to light up when electricity passes through it?
Ethanol
Dilute ethanoic acid
Solid lead(II) bromide
Tetrachloromethane
What are the products formed at the anode and the cathode during the electrolysis of molten magnesium oxide using carbon electrodes?
Anode: Oxygen
Cathode: Magnesium
Anode: Magnesium
Cathode: Oxygen
Anode: Hydrogen
Cathode: Oxygen
Anode: Oxygen
Cathode: Hydrogen
Table shows information about three chemical cells.
What is the possible potential difference of the chemical cell when metal Z is paired with W ?
0.3 V
1.2 V
1.5 V
2.1 V
Diagram shows the electrolysis of concentrated copper(II) chloride solution using carbon as electrodes.
Which of the followings is the correct half equations represents the reactions at the anode?
4OH- → 2H2O + O2 + 4e
2Cl- → Cl2 + 2e
Cu → Cu2+ + 2e
Cu2+ + 2e → Cu
Diagram
shows the apparatus set-up for the electrolysis of 1.0 mol dm -3 sodium chloride solution using carbon electrodes.Which of the following are the observation for the electrolysis process shown in Diagram?
Grey solid deposited on electrode B
Colourless gas is released at electrode B
Carbon electrode A becomes thinner
Greenish yellow gas is released at electrode A
Molten X is electrolysed using carbon electrodes. After 10 minutes, a brown solid is deposited on the cathode and a brown gas is released at the anode. What is molten X?
Lead(II) chloride
Lead(II) bromide
Copper(II) chloride
Copper(II) bromide
Table shows the results of the electrolysis of molten lead (II) bromide.
The ammeter only shows reading when solid lead (II) bromide, PbBr2 is completely melted. Which of the following explains the observation?
Bromide ions receive electrons to form bromine gas
Lead (II) ions donate electrons to produce lead metal
In the solid state, bromide and lead (II) ions are held in a lattice
Electrical conductivity occurs throughout
the whole experiment
Which of the following reactions shows that copper is oxidized?
Reaction of magnesium with copper (II)
oxide
Reaction of copper with silver nitrate solution
Electrolysis of copper (II) nitrate
solution by using carbon nitrate
Voltaic cell with copper and magnesium
electrodes in dilute sulphuric acid
Diagram shows an electrolysis of dilute sulphuric acid.
What could be gas X and the half-equation occurring at the cathode?
Carbon dioxide, C + O2 → CO2
Hydrogen, 2H+ + 2e- ®H2
Oxygen, 4OH- → H2O + O2 + 4e-
Sulphur dioxide, SO4 2- → SO2 + O2 + 2e-
Diagram shows an apparatus set-up for a chemical cell. What can you observed from this experiment?
Hydrogen gas is liberated at the copper plate
Magnesium electrode becomes thinner
Colourless solution turns to brown
Electron flows from magnesium to the copper plate
The negatively charged ions (anions) are attracted to the ________.
anode
cathode
Anions get discharged by ________ electrons at the ___________
gaining, cathode
losing, anode
gaining, anode
losing, cathode
What ions are present in molten aluminium oxide?
Al3+, O2-, H+, OH-
Al3+, O2-
Al3+, OH-
___________ electrode is an inert electrode.
Copper
Iron
Carbon
Zinc
What is the ore of aluminium called?
Baxite
Bauxite
Cryolite
Malachite
The electrodes in electrolysis of aluminium are made of
Steel
Anodes
Graphite
Plastic
What do you add to aluminium ore to reduce its melting temperature?
Dendrite
Malachite
Bauxite
Cryolite
When concentrated NaCl solution is electrolysed what has forms at the anode?
Different pairs of metals produce different voltages.
True
False
The closer the elements in the Electrochemical Series, the greater the voltage produced.
True
False
Electrons will flow from the element higher in the Electrochemical Series to the one lower in the Electrochemical Series.
True
False
