General Principles and Processes of Isolation of Elements Quiz - ICSE Class 12 Chemistry

Free practice quiz: General Principles and Processes of Isolation of Elements (ICSE Class 12 Chemistry). 50 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

This ICSE Class 12 Chemistry practice quiz has 50 multiple-choice questions on General Principles and Processes of Isolation of Elements, and 50 of them come with an explanation. Try the 5 sample questions below (tap an option to check yourself), then play the full quiz online. No sign-up needed.

Sample questions

1. Which of the following methods is most suitable for the extraction of highly electropositive metals like sodium from their molten chlorides?

   1. Electrolytic reduction
   2. Smelting with carbon
   3. Froth floatation
   4. Leaching with cyanide
   Show answer

   Answer: A. Electrolytic reduction

   Highly electropositive metals like sodium have very negative standard electrode potentials. Their oxides or chlorides are very stable. Electrolytic reduction of their molten salts is the most effective method for their extraction because it uses electrical energy to overcome the large negative free energy change associated with their reduction. Smelting with carbon is not suitable as carbon is less electropositive than sodium and cannot reduce sodium chloride. Froth floatation and leaching are concentration techniques, not reduction methods.

2. The refining of nickel is commonly done by the Mond process. This process is based on the property of nickel to form a volatile compound with carbon monoxide at moderate temperatures. What is the chemical formula of this compound?

   1. Ni(CO)₄
   2. Ni₂C
   3. Ni(CO)₅
   4. NiC₂O₄
   Show answer

   Answer: A. Ni(CO)₄

   The Mond process is used for the purification of nickel. In this process, impure nickel is heated in a stream of carbon monoxide at about 330-350 K. Nickel reacts with carbon monoxide to form nickel tetracarbonyl, Ni(CO)₄, which is a volatile liquid. Impurities like iron and copper do not react with carbon monoxide under these conditions. The volatile Ni(CO)₄ is then decomposed at about 450-470 K to deposit pure nickel as a fine powder (Ni(CO)₄ → Ni + 4CO).

3. Which of the following methods is suitable for the extraction of tin from stannic oxide (SnO₂)?

   1. Electrolytic reduction of molten SnO₂
   2. Reduction of SnO₂ with hydrogen
   3. Reduction of SnO₂ with carbon
   4. Reduction of SnO₂ with aluminium
   Show answer

   Answer: C. Reduction of SnO₂ with carbon

   Tin is extracted from its principal ore, cassiterite (SnO₂), by reduction with carbon in a reverberatory furnace or a blast furnace. The reaction is: SnO₂(s) + 2C(s) → Sn(l) + 2CO(g). While hydrogen can also reduce tin oxide, carbon is more economical for large-scale industrial production. Electrolytic reduction of molten SnO₂ is not the primary method. Aluminium is a stronger reducing agent but is more expensive than carbon.

4. Which of the following is NOT a reducing agent used in the extraction of metals?

   1. Carbon monoxide
   2. Carbon
   3. Aluminium
   4. Oxygen
   Show answer

   Answer: D. Oxygen

   Reducing agents are substances that donate electrons or cause reduction in other substances. Carbon monoxide, carbon, and aluminium are all commonly used as reducing agents in the extraction of metals. Oxygen, on the other hand, is an oxidizing agent; it causes oxidation by accepting electrons or by oxidizing other substances.

5. The term 'smelting' is best described as:

   1. The process of heating an ore in the absence of air
   2. The process of heating an ore with a flux and a reducing agent
   3. The process of dissolving a metal from its ore
   4. The process of purifying a metal by electrolysis
   Show answer

   Answer: B. The process of heating an ore with a flux and a reducing agent

   Smelting is a pyrometallurgical process that involves heating an ore, typically in a furnace, with a flux and a reducing agent to a high temperature, causing chemical reduction and phase change to extract the desired metal in a molten state. This process is used to separate the metal from its ore and impurities.

More questions in this quiz

Answers and explanations are in the full quiz.

1. In the extraction of copper by electrolytic refining, the impure copper is made the anode and a thin strip of pure copper is made the cathode. What substance forms the 'anode mud'?
2. The process of calcination is primarily used to:
3. Bauxite, the principal ore of aluminium, is purified by:
4. Zone refining is a purification technique used for metals like silicon and germanium. This method relies on the principle that:
5. In the extraction of zinc from zinc blende (ZnS), which of the following steps is INCORRECT or not typically employed?
6. Chromite ore, FeCr₂O₄, is converted to sodium dichromate by a series of reactions. Which of the following is NOT a part of this process?
7. The Ellingham diagram plots the free energy of formation of metal oxides as a function of temperature. A metal oxide line that lies below the carbon monoxide line at a given temperature indicates that:
8. Thermite welding uses a mixture of iron(III) oxide and aluminium powder. The reaction is highly exothermic and produces molten iron. This process is an example of:
9. Which of the following statements is INCORRECT regarding the cyanide process for the extraction of silver?
10. In the blast furnace, the reduction of iron oxides to iron occurs in different temperature zones. Which of the following is the primary reducing agent in the lower temperature zone (around 500-700 K)?
11. The process used for the extraction of copper from its sulphide ore (Cu₂S) by heating in the presence of air after initial concentration and roasting is called:
12. Which of the following ores is concentrated by froth flotation using pine oil as a frother and potassium ethyl xanthate as a collector?
13. In the extraction of aluminium by the Hall-Héroult process, cryolite (Na₃AlF₆) is added to molten alumina (Al₂O₃). What is the primary function of cryolite?
14. Which of the following methods is used for the refining of crude copper to obtain high purity copper?
15. The principle behind the cyanide process for gold extraction is leaching by forming a complex. The chemical species formed is:
16. Which of the following metals is extracted by leaching with sodium cyanide followed by displacement with zinc?
17. In the Smelting process, a reducing agent is added to the ore. Which of the following is NOT a common reducing agent used in smelting?
18. The basic flux used in smelting of acidic ores like silica (SiO₂) is:
19. In the extraction of aluminium by the Hall-Héroult process, the electrolyte consists of molten cryolite and alumina. Which of the following statements about the electrodes is correct?
20. The chemical treatment of zinc blende (ZnS) with sodium carbonate solution in the cyanide process is an example of:
21. A metal X is extracted by heating its oxide in the presence of carbon. The metal X is purified by passing its vapour over heated platinum. The metal X is likely:
22. In the context of the Ellingham diagram, a steeper negative slope for a metal oxide formation line indicates:
23. Which of the following ores is concentrated by leaching with dilute acid, followed by precipitation of the metal using a more electropositive metal?
24. Which of the following statements is FALSE regarding the extraction of Aluminium by the Hall-Héroult process?
25. Van Arkel method is used for the purification of titanium. This method involves:
26. In the blast furnace operation, the molten slag formed is a mixture of:
27. The process of recovering metals like gold and silver from their ores using cyanide solution is known as:
28. The extraction of mercury from cinnabar (HgS) typically involves roasting in air followed by reduction. What is the initial product of roasting HgS in limited air?
29. The Dow process is used for the extraction of which metal?
30. Which of the following statements about the reduction of metal oxides by carbon is generally true based on the Ellingham diagram?
31. The basic lining of a blast furnace is made of:
32. In the electrolytic reduction of molten NaCl to obtain sodium metal, which of the following occurs at the cathode?
33. Chromium is extracted from chromite ore (FeCr₂O₄) by first converting it to sodium dichromate. Which of the following reagents is used to convert sodium chromate (Na₂CrO₄) solution to sodium dichromate (Na₂Cr₂O₇)?
34. Which of the following metals cannot be extracted by electrolysis of its molten oxide?
35. The process of roasting is carried out in the presence of air. Which of the following is a primary objective of roasting?
36. Which metal has its extraction process involving the electrolysis of its aqueous solution?
37. In the context of the Ellingham diagram for metal oxides, if the graph for the formation of an oxide is a horizontal line, it implies:
38. Which of the following processes is used to extract highly reactive non-metals like fluorine?
39. In the electrolytic refining of silver, the anode mud contains:
40. The Kroll process is used for the extraction of:
41. Which of the following metals is obtained by the electrolytic reduction of its fused anhydrous chloride?
42. Thermite is a mixture of Fe₂O₃ and Al powder. The reaction is highly exothermic. This is an example of:
43. The refining of crude silver is done by the process of:
44. Which of the following ores is concentrated using the magnetic separation method?
45. Which substance acts as a flux in the blast furnace for iron extraction when the gangue is acidic?

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