Electrochemistry and Metal Extraction

Multiple Choice Quiz

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You will get a different set of questions each time you attempt this quiz.

The electrochemical series is a list of elements in the order in which they tend to lose electrons.
From the following select the list which has the elements in decreasing order of reactivity.
1. Potassium, magnesium, zinc, silver, gold
2. Sodium, magnesium, aluminium, silver, copper
3. Potassium, sodium, silver, magnesium, aluminium
4. Sodium, silver, magnesium, lead, mercury
Select two correct statements about the Reactivity Series from the following:
1. The least reactive elements are at the bottom.
2. They lose their electrons less readily as you go down the series.
3. They are all metals.
4. They are in the same order as the Activity Series.
The first known battery constructed with copper and zinc plates was known as a Voltaic Pile. Which one of the following scientists was credited with its discovery.
1. Alessandro Volta
2. Michael Faraday
3. Humphrey Davy
4. Luigi Galvani
Which one of the following scientists is credited with discovering a number of metals by passing an electric current through a molten sample of the metal's ore?
1. Humphrey Davy
2. Alessandro Volta
3. Luigi Galvani
4. Michael Faraday
When molten lead bromide (PbBr) is electrolysed, which one of the following does not occur?
1. Oxygen gas (O₂) forms at the anode.
2. Lead (Pb) metal deposits at the cathode.
3. The cathode reaction is:
  Pb²⁺ + 2e^- ---> Pb
4. The reaction only occurs when the lead bromide is molten.
Which one of the following metals is least likely to corrode?
1. Copper
2. Magnesium
3. Potassium
4. Lead
5. Iron
Based on its position in the Reactivity Series, aluminium does not corrode as easily as it would be predicted.
Why is this?
1. It forms a thin layer of aluminium oxide on its surface that prevents further corrosion.
2. It is the least dense metal in the Reactivity Series.
3. It has a full outer shell of electrons.
4. It is a very unreactive metal.
Select three factors suggesting why aluminium is very suitable in making windows and doors.
1. Aluminium has a relative low density.
2. Aluminium doesn't corrode easily.
3. Aluminium is a strong metal.
4. Aluminium can be bent easily.
5. Aluminium has a nice colour.
Select three factors which aid the corrosion of iron.
1. Iron in contact with water.
2. Oxygen present around the iron.
3. Presence of salt.
4. Low temperature of iron sample.
Which one of the following, if coated on a metal, would be least likely to prevent corrosion?
1. White spirit
2. Grease
3. Oil
4. Paint
The rusting of iron may be prevented by galvanising.
What is meant by the term 'galvanising'?
1. Coating the iron with zinc.
2. Coating the iron with chromium.
3. Coating the iron with tin.
4. Coating the iron with aluminium.
Which one of the following methods is used to prevent the corrosion of aluminium?
1. Anodising
2. Galvanising
3. Tin plating
4. Chromium plating
Cathodic Protection is a means of preventing iron from rusting.
Which one of the following statements about this method is incorrect?
1. A metal, which is lower than iron in the electrochemical series is connected to the iron.
2. The other metal corrodes first in preference to the iron.
3. This method is also known as 'sacrificial protection'.
4. This method is used to prevent corrosion of ships.
Stainless steel is an alloy consisting of iron and a non-metal.
What is this non-metal?
1. Carbon
2. Sulfur
3. Oxygen
4. Silicon
Which metal is extracted from its ore using the Down's Cell?
1. Sodium
2. Iron
3. Aluminium
4. Chromium
In the Down's Cell, what is mixed with the sodium chloride in order to reduce its melting point?
1. CaCl₂
2. MgCl₂
3. MgO
4. KCl
In the diagram of the Downs Cell shown, name the parts labeled X, Y and Z.
1. X = positive electrode, Y = negative electrode, Z = steel gauze.
2. X = positive electrode, Y = steel gauze, Z = negative electrode.
3. X = negative electrode, Y = positive electrode, Z = steel gauze.
4. X = negative electrode, Y = steel gauze, Z = positive electrode.
What is the function of the steel gauze in the Downs Cell?
1. To prevent the sodium and chlorine coming into contact and reacting.
2. It acts as a catalyst during the process.
3. It is the negative electrode.
4. It removes any impurities from the sodium.
Which one of the following reactions occurs at the anode in the Downs cell?
1. 2Cl^- → Cl₂ + 2e^-
2. 2Na⁺ +2e^- → 2Na
3. 2NaCl → 2Na + Cl₂
4. Cl₂ + 2OH^- → H₂ + 2ClO^-
From which ore is aluminium extracted?
1. Bauxite
2. Pyrite
3. Haematite
4. Cryolite
In extracting aluminium, its ore is initially mixed with a hot solution to form sodium aluminate.
What is this solution mainly composed of?
1. Sodium hydroxide (NaOH)
2. Sodium carbonate (Na₂CO₃)
3. Sodium chloride (NaCl)
4. Sodium hydrogen carbonate (NaHCO₃)
In the extraction of aluminium, solid impurities settle as a coloured mud.
What colour is this mud?
1. Red
2. Brown
3. Black
4. Grey
5. Blue
During the extraction of aluminium, alumina is electrolysed. Before the electrolysis the alumina is mixed with Na₃AlF₆.
What is the common name for Na₃AlF₆?
1. Cryolite
2. Dolomite
3. Bauxite
4. Haematite
During the electrolysis of alumina to produce aluminium, which one of the following is not true?
1. Chlorine gas is produced at the anode.
2. The temperature of the electrolyte is around 950^oC.
3. Aluminium is removed as it is being formed.
4. The reaction occurring at the cathode is:
  Al³⁺ + 3e^- → Al
During the manufacture of aluminium windows and doors, the aluminium is anodised in sulfuric acid (H₂SO₄).
What is the reason for anodising the aluminium?
1. To give the aluminium a thicker coating of oxide.
2. To give the aluminium a more pleasing colour.
3. To soften the aluminium in order to make it easier to shape.
4. To remove impurities from the aluminium.
Which one of the following is not a general property of the transition metals?
1. They form oxides that are soluble in water.
2. They have variable valencies.
3. They are good catalysts.
4. They form coloured ions.
In the blast furnace used for the extraction of iron, what three substances are added at X in the diagram?
1. Iron ore
2. Coke
3. Limestone
4. Slag
5. Silicon oxide
6. Graphite
In extracting iron using the blast furnace shown, what are the processes happening at A, B and C?
1. A = hot gases released, B = hot air enters, C = slag comes out
2. A = hot gases released, B = hot air enters, C = iron comes out
3. A = hot gases enter, B = hot air released, C = slag comes out
4. A = hot gases enters, B = iron comes out, C = slag comes out
In the manufacture of steel, which three of the following statements are correct?
1. Oxygen is blown through the molten iron.
2. Carbon and sulfur impurities are removed from the molten iron.
3. Chromium is added to increase the resistance of steel against corrosion.
4. Vanadium is added to the steel to give it extra hardness.
The electric arc furnace is used to
1. recycle scrap iron.
2. add metals to iron in order to make alloys.
3. make steel structures for building.
4. coat iron in order to stop it corroding.
Which scientist was the first to isolate the elements sodium and potassium in 1807 by passing electricity through sodium hydroxide and potassium hydroxide respectively?
1. Humphry Davy
2. Luigi Galvani
3. Michael Faraday
4. Albert Einstein
Name two metals, one a main group metal, the other a transition element, both of which are protected from further corrosion by the oxide layer that forms on their surfaces.
1. Aluminium and zinc
2. Aluminium and iron
3. Lithium and iron
4. Sodium and zinc
How does a sacrificial anode protect a metal?
1. It is more easily oxidised than the protected metal.
2. It forms an impenetrable layer over the protected metal.
3. It reacts with the metal to give it a greater resistance to corrosion.
4. It is reduced more readily than the metal.
Where in Ireland is bauxite purified to produce alumina?
1. Aughinish
2. Drogheda
3. Ringaskiddy
4. Wicklow
Give two reasons why it is preferable to obtain aluminium from recycling rather than extracting it from its ore.
1. Recycled aluminium is cheaper.
2. It reduces waste.
3. It is a purer form of aluminium.
4. Recycled aluminium has greater strength.
The balanced equation for the reactions taking place at the negative electrode in the electrolysis of alumina is:
1. Al³⁺ + 3e^– → Al
2. Al⁺ + e^– → Al
3. 3Al⁺ + 3e^– → Al
4. Al → Al³⁺ + 3e^–
The balanced equation for the reactions taking place at the positive electrode in the electrolysis of alumina is:
1. 6O^2- - 12e^– → 3O₂
2. 6O^2- + 12e^– → 3O₂
3. 3O₂ → 6O^2- - 12e^–
4. Al³⁺ + 3e^– → Al
What is the function of cryolite (Na₃AlF₆) in the electrolysis of alumina?
1. To lower the melting point of the aluminium oxide.
2. To act as a solvent for the aluminium oxide.
3. It acts an inert electrode during the electrolysis.
4. It reacts with the aluminium oxide to form pure aluminium.
Select two reasons from the following as to why recycling of aluminium metal is important for the protection of the environment.
1. It prevents litter.
2. It saves the energy that would have been used in producing aluminium by electrolysis.
3. Recycled aluminium is easier to shape.
4. Recycling aluminium produces less ozone.
How does the anodising of aluminium protect it from corrosion?
1. A protective layer is formed over the aluminium.
2. It removes impurities that may cause corrosion of aluminium.
3. It reacts with impurities on the surface of the aluminium.
4. It forms a layer of aluminium hydroxide on the surface of the aluminium that prevents further corrosion.
A blast furnace may be used in the extraction of iron from iron ore.
What four materials must be added to a blast furnace in operation?
1. Iron ore
2. Coke
3. Limestone
4. Hot air
5. Haematite
6. Cryolite
7. Aluminium oxide
A blast furnace may be used in the extraction of iron from iron ore.
What is the principal reducing agent in the blast furnace?
1. Carbon monoxide
2. Coke
3. Limestone
4. Iron ore
Why can very electropositive metals such as sodium only be extracted from their ores by electrolysis?
1. They have a very high tendency to lose electrons.
2. They have a very low tendency to lose electrons.
3. They are highly soluble in water.
4. They are very reactive with water.
Sodium metal is extracted from its ore using the Downs cell.
Explain why the electrolyte used in the Downs cell is molten.
1. In order that the ions can move around.
2. So that the molten ore dissolves in water.
3. In order to oxidise the sodium.
4. This reaction needs a very high temperature before it can take place.
Sodium metal is extracted from its ore using the Downs cell.
What is the balanced equation for overall reaction in the Downs cell?
1. NaCl → Na + ½Cl₂
2. Na⁺ + Cl^- → NaCl
3. NaCl → Na⁺ + Cl^-
4. NaCl → Na + Cl
Sodium metal is extracted from its ore using the Downs cell.
In what two ways are the products prevented from recombining after they have been formed by electrolysis?
1. The products are separated by a steel gauze.
2. The sodium is removed as it is being formed.
3. Calcium chloride is added to the sodium chloride to prevent the products recombining.
4. Sodium falls to the bottom of the cell where it collected, and the chlorine gas escapes at the top.
Sodium metal and chlorine gas are extracted from sodium chloride using the Downs cell.
Select a correct combination of commercial uses for each of these products.
1. Sodium is used in street lighting, and chlorine is used in disinfecting swimming pools.
2. Sodium is used as a coolant in nuclear reactors, and chlorine is used in manufacturing margarine.
3. Sodium is used in manufacturing margarine, and chlorine is used in disinfecting swimming pools.
4. Sodium is used in manufacturing ammonia, and chlorine is used as a jet fuel.
The blast furnace may be used in the extraction of iron from iron ore.
Which one of the following is the correct balanced equation for the reaction between haematite (Fe₂O₃) and carbon monoxide (CO)?
1. Fe₂O₃ + 3CO → 2Fe + 3CO₂
2. Fe₂O₃ + 3CO → 2FeO + 2CO₂
3. Fe₂O₃ + CO → 2FeO + O₂ + CO₂
4. Fe₂O₃ + 3CO₂ → 2FeO + 3CO₂
In the blast furnace, pig iron is produced as an intermediate product. The pig iron is then converted into steel.
Select a reason why the pig iron produced in a blast furnace is further processed into steel?
1. Pig iron is too brittle to be of any use.
2. Pig iron rusts easily.
3. Pig iron cannot be easily melted.
4. The pig iron is too pure to be used.
Select three ways in which steel differs from the iron produced in a blast furnace.
1. Steel is not as brittle as pig iron.
2. Steel has a lower carbon content.
3. Steel is more resistant to corrosion.
4. Steel is cheaper to produce than pig iron.