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

Why is pure gold not used for making ornaments?

  1. It is very costly.

  2. It melts at low temperature.

  3. It has high density.

  4. It is soft.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Pure 24-karat gold is too soft to maintain its shape in ornaments. It's typically alloyed with metals like copper or silver to increase durability and hardness while maintaining luster.

Multiple choice

Which of the following statements is correct? A. Down’s Process: Metallic sodium by the electrolysis of fused NaCl B. Dow’s Process: Magnesium from sea water by electrolysis of MgCl2 C. Solvay Process: Manufacture of NaCO3

  1. Only A

  2. Only B

  3. Only C

  4. A and B

  5. A, B and C
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Both statements are correct. A. Down’s Process: Metallic sodium by the electrolysis of fused NaCl.  B. Dow’s Process: Magnesium from sea water by electrolysis of MgCl2.

Multiple choice

Laterite is produced by which of the following methods?

  1. Hydration and carbonation

  2. Hydrolysis and oxidation

  3. Leaching and oxidation

  4. Hydration and calcification
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Laterite soil is formed through the process of leaching and oxidation in tropical regions with high rainfall. Heavy rainfall washes away soluble minerals like silica and bases, leaving behind iron and aluminum oxides which give laterite its characteristic red color. This is distinct from hydration-carbonation or calcification processes.

Multiple choice

Which of the following properties of an alloy in a heating element used in a heater is true?

  1. An alloy does not consist of any metal

  2. Alloys decrease the tensile strength by adding a carbon agent.

  3. Alloys have very high resistance

  4. Alloy is designed to be able to operate at low temperatures.

  5. Alloys have a high melting point
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The heating element of the heater is made up of an alloy which has very high resistance so when current flows through the heating element, it becomes hot and glows red.

Multiple choice

Why are coils of electric irons made of an alloy instead of using pure metal?

  1. Alloys oxidise quickly

  2. Alloys are mechanically weak

  3. Alloys better withstand less heat before melting

  4. Alloys have low resistivity than pure metal

  5. Alloys have a higher melting point
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Alloys have a higher melting point than pure metal. So, the coils of electric irons are made of an alloy.

Multiple choice

Directions: For this question, select the best of the answer choices given.

An experimental microwave clothes dryer heats neither air nor cloth. Rather, it heats water on clothes, thereby saving electricity and protecting delicate fibers by operating at a lower temperature. Microwaves are waves that usually heat metal objects, but developers of a microwave dryer are perfecting a process that will prevent thin metal objects such as hairpins from heating up and burning clothes. Which of the following, if true, most strongly indicates that the process, when perfected, will be insufficient to make the dryer readily marketable?

  1. Metal snap fasteners on clothes that are commonly put into drying machines are about the same thickness as most hairpins.

  2. Many clothes that are currently placed into mechanical dryers are not placed there along with hairpins or other thin metal objects.

  3. The experimental microwave dryer uses more electricity than future, improved models would be expected to use.

  4. Drying clothes with the process would not cause more shrinkage than the currently used mechanical drying process causes.

  5. Many clothes that are frequently machine-dried by prospective customers incorporate thick metal parts such as decorative brass studs or buttons.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

The argument assumes that preventing hairpins from heating will solve the metal heating problem. Option E weakens this by showing that many clothes have thick metal parts (studs, buttons) that would still heat up in a microwave dryer. Even if thin metal objects don't heat, thick metal parts still would, making the dryer unsafe for most commercially machine-dried clothes.

Multiple choice

Which of the following statements is/are true? P. The silicon carbide is used as a refractory material. Q. Blast furnace is used for the smelting of lead ore. R. Calamine and casseterite are the ores of zinc.

  1. P only

  2. Q only

  3. R only

  4. P and Q

  5. Q and R
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The substances that are capable of withstanding very high temperatures without melting or becoming soft are called refractory materials like- SiC (carborundum), Al2O3, SiO2, etc. Blast furnace is used for the smelting of iron, copper and lead ores. Calamine (ZnCO3) is the ore of zinc while casseterite (SnO2) is the ore of Sn.

Multiple choice

Identify the incorrect statement(s). A. Mild steel contains 0.30% to 0.60% of carbon. B. Promoted iron is used as the catalyst in the Haber-Bosch process of NH3 production. C. In the quenching process of mild steel, water or oil is used.

  1. A only

  2. B only

  3. C only

  4. A and B

  5. B and C
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A. Mild steel contains 0.15% to 0.30% of carbon. Medium steel has 0.30% to 0.60% of carbon. B. Promoted iron is used as the catalyst in the Haber-Bosch process for the making of NH3. C. Mild steel is malleable and can be bent or machined. This is hardened (tempered) by heating to red heat and quenched by plunging into water or oil.

Multiple choice

Which of the following processes is/are related to lead refining?

P. Parkes process Q. Pattison process R. Fire process

  1. P only

  2. Q only

  3. R only

  4. P and Q

  5. Q and R
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

P. The Parkes process, patented in 1850, uses zinc to form a material which the silver enters. This floats on the lead and can be skimmed off.
Q. The Pattison process was patented by its inventor, Hugh Lee Pattinson, in 1833. It depended on well-known material properties; essentially that lead and silver melt at different temperatures. The equipment consisted of a row of about 8-9 iron pots, which could be heated from below. Argentiferous lead was charged to the central pot and melted. This was then allowed to cool, as the lead solidified, it was skimmed off and moved to the next pot in one direction, and the remaining metal was then transferred to the next pot in the opposite direction. The process was repeated in the pots successively, and resulted in lead accumulating in the pot at one end and silver in that at the other. R. Fire process - The initial product of copper smelting was impure black copper, which was then repeatedly melted to purify it, alternately oxidizing and reducing it. In one of the melting stages, lead was added. Gold and silver preferentially dissolved in this, thereby providing a means of recovering these precious metals. To produce purer copper suitable for making copper plates or hollow-ware, further melting processes were undertaken, using charcoal as fuel. The repeated application of such fire-refining processes was capable of producing copper that was 99.25% pure.

Multiple choice

Directions: Consider the following Assertion A and Reason R statements and select the correct option. Assertion A: If pure haematite is used as an ore for iron extraction, there is no need of roasting. Reason R: The final product of the roasting process is FeO3 in the extraction of iron.

  1. A is true but R is false.

  2. A is false but R is true.

  3. Both A and R are true.

  4. Both A and R are false.

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In case of extraction of iron, in roasting step all taken pure haematite converted to FeO that combines with oxygen and form Fe2O3. So, the final product of the roasting step is FeO3 in the extraction of iron and thus there is no need of roasting.

Multiple choice

Stainless steel is

  1. an element

  2. a compound

  3. a mixture of non-metals

  4. a metal alloy
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Stainless steel is an alloy (mixture) primarily composed of iron, carbon, and chromium (minimum 10.5%). The chromium forms a protective oxide layer that prevents rust and corrosion. It is not a pure element, nor a compound, nor a mixture of only non-metals.