Basic Metallurgical Processes MCQs Quiz | Class 10

This quiz is designed for Class X students studying Science (Code 086) under Unit I: Chemical Substances – Nature and Behaviour. It specifically focuses on the topic Basic Metallurgical Processes, covering key concepts such as concentration of ores, roasting vs calcination, reduction techniques, and the basic outline of refining. Test your understanding by answering 10 multiple-choice questions, check your score immediately, and download the detailed PDF answer sheet for revision.

Overview of Basic Metallurgical Processes

Metallurgy involves the extraction of metals from their ores and refining them for use. For Class 10 Science (Unit I), the process is generally divided into three major steps based on the reactivity of the metal: concentration of ore, extraction of crude metal, and refining.

1. Concentration of Ore

Ores mined from the earth are usually contaminated with large amounts of impurities such as soil and sand, called gangue. Removing these impurities prior to extraction is known as concentration or enrichment. Methods include gravity separation, froth floatation, and magnetic separation.

2. Extraction of Metals

The method of extraction depends on the metal’s position in the reactivity series:

  • Metals of Low Reactivity: These can be reduced to metals by heating alone (e.g., Cinnabar, HgS).
  • Metals of Medium Reactivity: Found as carbonates or sulphides. They are first converted to oxides.
    • Roasting: Heating sulphide ores in excess air (e.g., ZnS becomes ZnO).
    • Calcination: Heating carbonate ores in limited air (e.g., ZnCO3 becomes ZnO).
    • Reduction: The oxide is then reduced using Carbon (Coke) or highly reactive metals like Aluminium (Thermit process).
  • Metals of High Reactivity: Extracted by electrolytic reduction of their molten chlorides or oxides (e.g., Sodium, Magnesium, Aluminium). Carbon cannot reduce their oxides due to high affinity for oxygen.

3. Refining of Metals

The metal obtained after reduction is often not pure. Electrolytic refining is widely used, especially for Copper. In this process:

  • Anode: Impure metal block.
  • Cathode: Thin strip of pure metal.
  • Electrolyte: Salt solution of the metal.
  • Anode Mud: Insoluble impurities settle at the bottom.

Comparison: Roasting vs Calcination

Feature Roasting Calcination
Ore Type Sulphide Ores Carbonate Ores
Air Supply Excess Air Limited or No Air
Gas Produced Sulphur Dioxide (SO2) Carbon Dioxide (CO2)

Extra Practice Questions

  • 1. Why is Aluminium used in the Thermit reaction? (Ans: High affinity for oxygen, acts as a reducing agent).
  • 2. What is the formula of Cinnabar? (Ans: HgS).
  • 3. Name the method used to concentrate magnetic ores. (Ans: Magnetic Separation).
  • 4. What happens to the impurities during electrolytic refining? (Ans: Soluble ones go into solution; insoluble ones form anode mud).
  • 5. Which gas is released when Zinc Carbonate is heated strongly? (Ans: Carbon Dioxide).