This set of Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “Uses of Aluminium, Copper, Zinc and Iron”.
1. Which metal is used for galvanising iron?
Explanation: Zinc is used for galvanising iron to protect it from corrosion. Galvanisation is a process of applying a protective zinc coating on iron or steel to prevent it from rusting. The most common method in galvanising is hot-dip method.
2. Zinc dust is used as a reducing agent in the manufacture of paints.
Explanation: Yes, zinc dust is a strong reducing agent used in the laboratory. It is also used in the manufacturing of drugs. It is used as a precipitant for many metals like copper, iron, aluminium to purify the solution containing metals.
3. Which of the following metals is a good conductor of electricity and conducts electricity twice as much as the other elements?
Explanation: Aluminium is light, cheapmetal and good conductor electricity and resists corrosion. It conducts electricity twice as that of copper. It is used for making transmission cables and for winding the moving coil of dynamos or motor.
4. In thermite process, what is the reducing agent used?
Explanation: Thermite process proceeds via a thermite reaction. Thermite reaction involves the oxidation of the metal aluminium by the oxide of another metal, usually iron oxide. In this reaction, since aluminium is the element being oxidised, it acts as a reducing agent.
5. What type of extraction is the carbon monoxide reduction process used for?
Explanation: The reduction of the ore. At the high temperature at the bottom of the furnace, carbon dioxide reacts with carbon to produce carbon monoxide. It is the carbon monoxide which is the main reducing agent in the furnace. In the hotter parts of the furnace, the carbon itself also acts as a reducing agent.
6. Which of the following is present in aluminium bronze alloy?
Explanation: Aluminium bronze is an alloy made up of aluminium and copper. Its percentage composition is 95% of aluminium and 5% of copper. It is mainly used for making coins. It is a light strong alloy with golden lustre and resistant to corrosion.
7. In invar, what is the composition of iron and nickel?
a) Fe-64%, Ni-36%
b) Ni-68%, Fe-32%
c) Fe-36%, Ni-64%
d) Fe-62%, Ne-38%
Explanation: Invar (FeNe36) is an alloy of steel which is a combination of iron and nickel. It’s percentage of the composition is 64% of Iron and 36% of Nickel. It’s mainly used for making watches. It has practically no coefficient of expansion.
8. What is the name of the alloy of copper called which contains a composition of 30-35% of zinc?
Explanation: Brass is an alloy of copper which contains 60% of copper and 40% of zinc. It is highly ductile in nature, corrosion resistant and is mainly used for making parts of machinery and condenser tubes. It is also used for making utensils.
9. Cast iron is the most important form of iron.
Explanation: Cast iron is the most important form of iron because of it’s resistance to abrasion and indentation, the ability to absorb energy and the ability to deform without fracture and the ability to return to original dimension after being deformed.
10. Which metal is used for making water and steam pipes?
Explanation: Copper is used because of its high thermal conductivity. This is higher than all other metals except silver, a precious metal. Copper has a 60% better thermal conductivity rating than aluminium and a 3,000% better rating than stainless steel.
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