CHEMISTRY - CLASS 12
UNIT 1: METALLURGY
Interior Study Material
2 Marks
Basic Concepts & Ores
- What is Metallurgy?
- What are the least reactive chemical reactive elements occur in native state?
- What are the reactive metals occur in combined state?
- What is mineral? Give an example.
- What is ore? Give an example.
- What are the process are involved in the extraction of metals from its ore in metallurgy?
2 & 3 Marks
Ore Compositions
- Write the ores and composition of Al.
- Write the ores and composition of Fe.
- Write the ores and composition of Cu.
- Write the ores and composition of Zn.
- Write the ores and composition of Pb and Tin.
- Write the ores and composition of Ag.
2, 3 & 5 Marks
Concentration of Ores & Leaching
- What is gangue? Give an example.
- What is the concentration of ore?
- What are the methods are used for the concentration of the ores?
- Write the factors to choose concentration method of a ore.
- Write the names of different types of leaching (Cyanide, Alkali, Ammonia, Acid).
- What is cementation?
- Explain the leaching of ZnS and PbS.
- Explain froth floatation method and the role of sodium cyanide & sodium carbonate.
- Explain gravity separation / hydraulic washing method.
- How will you separate the tin stone ore from the wolframite impurities? (Magnetic separation)
2, 3 & 5 Marks
Extraction of Crude Metal & Reduction
- Write the steps or process involved to extract the crude metals from the concentrated ore.
- Write the common methods used to convert the concentrated ore to metal oxide.
- Write the reactions of removal of impurities in roasting process.
- How is harmful effect of SO2 is prevented during roasting process?
- When C and CO can not be used as a reducing agent?
- What is flux? Write its type with examples.
- What is slag? Give examples.
- What is blistered copper?
- What is auto reduction?
- Explain aluminothermic process with an example.
- Explain the smelting process and extraction of iron from haematite.
2, 3 & 5 Marks
Thermodynamic Principles & Ellingham Diagram
- What is Ellingham diagram? Write its observations and limitations.
- Explain the thermodynamic principle involved in metallurgy.
- How will you predict thermodynamic feasibility of reduction of oxides of one metal by another metal in Ellingham diagram?
- When aluminium can be and can not be used as a reducing agent in Ellingham diagram?
- Explain the condition to use coke (carbon) as a reducing agent for FeO by using Ellingham diagram.
2, 3 & 5 Marks
Refining Processes & Uses
- What is refining process? Name the various processes involved.
- What is distillation?
- What is anode mud?
- Write the principle behind the zone refining method.
- Write the principle of vapour phase method.
- What is misawite? Write its use.
- What is liquation?
- Explain Mond's process for refining of nickel.
- Explain Van - Arkel method of refining for titanium and zirconium.
- Explain the electrochemical principles of metallurgy and Hall - Heroult process for aluminium.
- Write the uses of Al, Zn, Fe, Au, and alloys like stainless steel, nickel steel, and chrome steel.
Interactive Book Back Multiple Choice Questions
Q1. Bauxite has the composition:
a) Al2O3 b) Al2O3.nH2O c) Fe2O3.2H2O d) None of theseQ2. Roasting of sulphide ores gives the gas (A). (A) is a colourless gas. Aqueous solution of (A) is acidic. The gas (A) is:
a) CO2 b) SO3 c) SO2 d) H2SQ3. Which of the following reaction represents calcinations?
a) 2Zn + O2 → 2ZnO b) 2ZnS + 3O2 → 2ZnO + 2SO2 c) MgCO3 → MgO + CO2 d) both (a) and (c)Q4. The metal oxide which can not be reduced to metal by carbon is:
a) PbO b) Al2O3 c) ZnO d) FeOQ5. Which of the metal is extracted by Hall-Heroult process?
a) Al b) Ni c) Cu d) ZnQ6. Wolframite ore is separated from tinstone by the process of:
a) Smelting b) Calcination c) Roasting d) Electromagnetic separationQ7. Flux is a substance which is used to convert:
a) Mineral into silicate b) Infusible impurities to soluble impurities c) Soluble impurities to infusible impurities d) All of theseQ8. Which of the following ores is best concentrated by froth-flotation method?
a) Magnetite b) Haematite c) Galena d) CassiteriteQ9. In the extraction of aluminium from alumina by electrolysis, cryolite is added to:
a) Lower the melting point of alumina b) Remove impurities from alumina c) Decrease the electrical conductivity d) Increase the rate of reductionQ10. Which of the following plot gives Ellingham diagram?
a) ΔS Vs T b) ΔGº Vs T c) ΔGº Vs 1/T d) ΔGº Vs T2Book Back Descriptive Questions
Part 1: Basic Principles & Extraction
- What are the differences between minerals and ores?
- What are the various steps involved in the extraction of pure metals from their ores?
- What is the role of quick lime in the extraction of iron from its oxide Fe2O3?
- Which type of ores can be concentrated by froth flotation method? Give two examples for such ores.
Part 2: Refining & Thermodynamics
- Describe a method for refining nickel.
- Explain zone refining process with an example.
- Using the Ellingham diagram:
- Predict the conditions under which Aluminium might be expected to reduce magnesia.
- Predict the conditions under which Magnesium could reduce alumina.
- Is it possible to reduce Fe2O3 by coke at a temperature around 1200K?
- Give the uses of Zinc.
Part 3: Processes & Roles of Reagents
- Explain the electrometallurgy of aluminium.
- Explain the following terms with suitable examples: (i) Gangue (ii) Slag
- Give the basic requirement for vapour phase refining.
- Describe the role of the following in the process mentioned:
- Silica in the extraction of copper
- Cryolite in the extraction of aluminium
- Iodine in the refining of Zirconium
- Sodium cyanide in froth flotation
- Explain the principle of electrolytic refining with an example.
- The selection of reducing agent depends on the thermodynamic factor. Explain with an example.
- Give the limitations of Ellingham diagram.
- Write a short note on electrochemical principles of metallurgy.