Chemistry · Science General

Metallurgical Processes

1,403 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

In which of the following cases will the extent of corrosion be enhanced?

  1. If the metal is highly unreactive

  2. In the absence of carbon dioxide

  3. If impurities are present in the metal

  4. If the metal is coated with a layer of protective coating
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The corrosion will be enhanced: (a)  if impurities are present in the metal (b)  in the presence of carbon dioxide (c)  if the metal is highly reactive  

Multiple choice

The rate and extent of corrosion do not depend upon

  1. position in galvanic series

  2. relative areas of anodic and cathodic parts

  3. position in electrochemical series

  4. purity of metal
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This option is correct because electrochemical series does not provide a generalization to the rate of corrosion of elements as per their position in electrochemical series. For example: In Zn-Al couple, zinc is corroded and Al behaves as cathodic part. However, Al is above Zn in electrochemical series, which is due to the fact that Al develops strongly adhering oxide layer on its surface, thereby making effective electrode potential more positive.

Multiple choice

S in the crude oil can be removed by treating with

  1. iron oxide

  2. copper oxide

  3. zinc oxide

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

Sulfur in crude oil is commonly removed using copper oxide through processes like copper sweetening. The copper oxide reacts with sulfur compounds to form copper sulfide, effectively removing sulfur impurities. Iron oxide, zinc oxide, and magnesium oxide are not typically used for this specific desulfurization purpose.

Multiple choice

Why does 1 kg of iron occupy less space as compared to 1 kg sponge?

  1. Iron has less density than sponge.

  2. Iron has more density than sponge.

  3. Iron is hard but sponge is soft.

  4. Iron has magnetic property but sponge has not.

  5. Iron has lustre but sponge has not.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Yes, the density of the iron is more than sponge, due to this 1 kg iron occupies less space but sponge occupies more space.

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.