Chemistry · Science General

Metallurgical Processes

1,436 Questions

This section explores key metallurgical processes including ore concentration, pyrometallurgy, and metal refining. It also covers corrosion and the properties of refractory materials. These chemistry questions are relevant for engineering and science entrance tests.

Pyrometallurgy furnacesMetal refining techniquesCorrosion protection methodsOre concentrationAuto reduction process

Metallurgical Processes Questions

Multiple choice

Which of the following statements is true for the purification of copper?

  1. A pure copper rod is connected to the positive terminal of the battery and copper sulphate solution is the electrolyte.

  2. A pure copper rod is connected to the positive terminal of the battery and distilled water is the electrolyte.

  3. An impure copper rod is connected to the positive terminal of the battery and salty water is the electrolyte.

  4. An impure copper rod is connected to the positive terminal of the battery and copper sulphate solution is the electrolyte.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In the purification of copper, an impure copper rod is connected to the positive terminal, pure copper rod is connected to the negative terminal and an aqueous solution of a copper salt, usually copper sulphate, is used.

Multiple choice

Why is zinc-coated iron used in bridges?

  1. Zinc gives shiny appearance to iron.

  2. Zinc increases the strength of the structure.

  3. Zinc reacts with iron to produce an alloy which is less affected by temperature change, thereby preventing the structure from developing cracks.

  4. Zinc protects iron from rusting.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Zinc protects iron from rusting.

Multiple choice

Which of the following is not a necessary condition for electroplating?

  1. The article to be electroplated is always placed at cathode.

  2. The metal to be plated is made anode.

  3. The electrolyte must contain ions of the metal which is to be plated.

  4. A higher current for a short time should be used.

  5. A direct current and not A.C. current should be used.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A low current for a longer time should be used.

Multiple choice

Why metals lose their shine over a period of time?

  1. Because of the action of pollens in the air

  2. Because of air and moisture

  3. Because of being kept covered

  4. Because of coming in contact with other metals
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Metals, when kept open in the atmosphere, react with atmospheric air and water vapours and gradually lose their shine. 

Multiple choice

In the extraction of Al from Al2O3, which of the following is used?

  1. CaF2

  2. Na3AlF6

  3. CaCl2

  4. SiO2
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Na3AlF6 (cryolite) is used in the Hall-Heroult process for aluminum extraction because it dissolves Al2O3 at much lower temperatures (≈1000°C) than pure Al2O3 would melt (>2000°C), making electrolysis feasible. CaF2 is used as a flux in steelmaking, CaCl2 is a drying agent, and SiO2 is a component of the cell lining but not the flux.

Multiple choice

Which of the following statements is/are true about corrosion?

  1. In an electrochemical corrosion, corrosion occurs at anode, but rust is deposited at the cathode.
  2. Dry corrosion is slow process while wet corrosion is a fast process.
  3. In an electrochemical corrosion, corrosion does not depend on the size of the anodic part of the metal.
  4. Dry corrosion involves direct attack of the chemicals on the metal surface.

  1. Only 1, 2 and 3

  2. Only 2, 3 and 4

  3. Only 1, 3 and 4

  4. Only 1, 2 and 4

  5. All of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This option is correct because all are true. In an electrochemical corrosion, corrosion occurs at the anode but rust is deposited at the cathode, dry corrosion is slow process while wet corrosion is a fast process, and it involves direct attack of the chemicals on the metal surface.

Multiple choice

Which of the following forms of corrosion occurs due to the concentration difference of two regions of same metal component?

  1. Pitting corrosion

  2. Stress corrosion

  3. Uniform corrosion

  4. Galvanic corrosion

  5. Crevice corrosion
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Crevice corrosion occurs due to the concentration difference of two regions of the same metal component. Corrosion takes place at the part that is of lower concentration. Thus, this option is correct.

Multiple choice

Which of the following statements is/are correct?

  1. Metal cladding is a process of sandwiching a metal between two corrosion resistant metals.
  2. In galvanising, zinc protects iron sacrificially.
  3. Thinner reduces viscosity of paint and increases it elasticity.
  4. Anodic coating is done by a metal, which is situated after the base metal in the electrochemical series.

  1. Only 1 and 2

  2. Only 1, 2 and 3

  3. Only 3 and 4

  4. Only 2, 3 and 4

  5. Only 1, 2 and 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is correct because all the three statements are true.