Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
1. Which of the following is the poorest conductor of heat in comparison to other options?
[A] Silver
[B] Copper
[C] Lead
[D] Mercury
Show Answer
Correct Answer: C [ Lead ]
Notes:
Silver is best conductor of heat while among metals lead is poorest conductor of heat. Cooper and aluminum are good conductor while mercury is a poor conductor.
2. 2,4-D, which is sold as a weed killer of the broad-leaved weeds is a synthetic version of __:
[A] Auxin Hormone
[B] Cytokinin Hormone
[C] Xylitol
[D] None of them
Show Answer
Correct Answer: A [Auxin Hormone ]
Notes:
2,4-dichlorophenoxyacetic acid (2,4-dichlorophenoxyethanoic acid) is a synthetic auxin frequently used as a weed killer of broad-leaved weeds. When two herbicides 2,4,5-T and 2,4-D and mixed in equal parts, it is called Agent Orange, which was used by US in Vietnam war.
3. Which among the following types of glasses contains Cerium and other rare earths and has a high absorption of ultraviolet rays?
[A] Crookes Glass
[B] Pyrex Glass
[C] Flint Glass
[D] Crown Glass
Show Answer
Correct Answer: A [Crookes Glass]
Notes:
Crookes glass comprises Cerium oxide (CiO2) which sharply absorbs the ultraviolet rays from the sunlight. It is used in making lenses of eye glasses.
4. Calamine is an ore of which among the following?
[A] Zinc
[B] Copper
[C] Mercury
[D] Iron
Show Answer
Correct Answer: A [Zinc]
Notes:
Calamine is an ore that contains zinc carbonate along with impurities like iron oxide. Through smelting, the zinc carbonate in calamine can be reduced to extract pure zinc metal. Other common zinc ores are sphalerite (zinc sulfide) and smithsonite (zinc carbonate). So calamine is considered a zinc ore due to its zinc carbonate content.
5. The chemical oxygen demand COD test is commonly used to measure which of the following?
[A] amount of organic compounds in water
[B] amount of oxygen in water
[C] amount of oxygen in a chemical
[D] amount of oxygen used in a oxygenation process
Show Answer
Correct Answer: A [amount of organic compounds in water]
Notes:
chemical oxygen demand is a measure of water quality and is amount of organic pollutants found in surface water. Potassium permanganate has been used for many years to measure COD
6. Which set shows copper ores as Sulfide, Carbonate, Silicate respectively?
[A] Chalcopyrite, Azurite, Dioptase
[B] Azurite, Dioptase, Chalcopyrite
[C] Dioptase, Chalcopyrite, Azurite
[D] Dioptase, Azurite, Chalcopyrite
Show Answer
Correct Answer: A [Chalcopyrite, Azurite, Dioptase]
Notes:
Chalcopyrite is a major copper sulfide ore. Azurite is a copper carbonate mineral with formula Cu₃(CO₃)₂(OH)₂. Dioptase is a copper silicate mineral with formula CuSiO₃·H₂O. These match the deposit types in sulfide, carbonate, and silicate order respectively.
7. Which of the following chemicals is also known as "Vitriol of clay”?
[A] Aluminium sulphate
[B] Sodium silicate
[C] Zinc sulphate
[D] Copper(II) sulphate
Show Answer
Correct Answer: A [ Aluminium sulphate]
Notes:
Aluminium sulphate is also known as Vitriol of clay. It is soluble in water and is mainly used as a flocculating agent in the purification of drinking water
8. Brass is an alloy of which of the following metals?
[A] Copper and Tin
[B] Copper and Zinc
[C] Lead and Tin
[D] Zinc and Nickel
Show Answer
Correct Answer: B [Copper and Zinc]
Notes:
Brass is an alloy of copper and zinc (Cu and Zn). Lead is often added in concentrations of around 2% to enhance the machinability of brass.
9. Which of the following metal is the main constituent in Pewter alloy?
[A] Lead
[B] Zinc
[C] Tin
[D] Iron
Show Answer
Correct Answer: C [Tin]
Notes:
The term pewter covers a variety of alloys consisting primarily of tin. It is composed of 85–99% tin, mixed with copper, antimony, bismuth, silver or lead..
10. Which of the following statements is incorrect about Stainless Steel?
[A] it is also known as inox steel
[B] It is an alloy of Iron, cobalt and nickel
[C] It is corrosion resistant
[D] molybdenum is added to increase corrosion resistance in reducing acids
Show Answer
Correct Answer: B [It is an alloy of Iron, cobalt and nickel]
Notes:
Stainless steel is also known as inox steel. It is an alloy of Iron, chromium and nickel. It is corrosion resistant and molybdenum is added to increase corrosion resistance in reducing acids.
