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

Stainless steel is an alloy of

  1. iron, carbon and nickel

  2. iron and manganese

  3. iron, chromium and zinc

  4. iron, chromium and nickel
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Stainless steel is primarily an alloy of iron, chromium (10-30%), and nickel. Chromium provides corrosion resistance by forming a passive oxide layer, while nickel enhances strength and corrosion resistance. Carbon is present in small amounts but not a primary alloying element.

Multiple choice

Galvanised iron sheets have a coating of

  1. tin

  2. lead

  3. zinc

  4. chromium
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Galvanised iron is coated with zinc through a process called galvanisation. The zinc layer protects the underlying iron from rusting by acting as a sacrificial anode. Tin is used for tin plates, lead is toxic and not used for galvanising, and chromium is used for chrome plating.

Multiple choice

Which of the following is a chemical change?

  1. Rusting of iron

  2. Tempering of iron

  3. Melting of iron

  4. Bending of iron
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Rusting of iron is a chemical change because iron reacts with oxygen and water to form iron oxide (rust), which has different chemical properties than the original iron. The other options (tempering, melting, bending) are physical changes that don't alter chemical composition.

Multiple choice

Galvanisation is the deposition of

  1. zinc on iron

  2. aluminium on iron

  3. tin on iron

  4. copper on iron
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Galvanization is the process of applying a protective zinc coating to iron or steel. Zinc corrodes preferentially to iron (sacrificial protection), preventing rust. The claimed answer is correct.

Multiple choice

Which of the following statements is/are false? P. Sulphide ores are concentrated by froth floatation process. Q. Calcination is the process of heating the ores strongly in the presence of excess air. R. Roasting is the process of heating the ores strongly in the absence of air. S. The impurities present in the ores are called gangue.

  1. Only P

  2. P and Q

  3. Only R

  4. Q and R

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

This option is correct because calcination is the process of heating the ores strongly in the absence of air and roasting is the process of heating the ores strongly in the presence of excess air.

Multiple choice

Which of the following acts as a corrosion inhibitor to prevent electrochemical corrosion at the joints of dissimilar metals?

  1. Barium chromate

  2. Barium ferrate

  3. Barium nitrate

  4. Barium oxalate
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Barium chromate is a fine light yellow powder with the formula BaCrO4. It is an oxidizing agent, and produces a green flame when heated, the result of barium ions. It is used as a corrosion inhibitor to prevent electrochemical corrosion at the joints of dissimilar metals.

Multiple choice

Flux in metallurgy is used to remove all impurities from ores.The barium salt used as a flux is

  1. barium acetate

  2. barium borate

  3. barium carbonate

  4. barium chlorate
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Barium carbonate (BaCO3), also known as witherite, is a chemical compound used in rat poison, bricks, ceramic glazes and cement. Witherite crystallises in the orthorhombic system. It is widely used in the ceramics industry as an ingredient in glazes. It acts as a flux, a matting and crystallising agent and combines with certain colouring oxides to produce unique colours not easily attainable by other means.

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.