Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination.
11. Which of the following is the composition of vinegar?
[A] 65-75% solution of acetic acid in water
[B] 45-60% solution of acetic acid in water
[C] 28-35% solution of acetic acid in water
[D] 5-8% solution of acetic acid in water
Show Answer
Correct Answer: D [5-8% solution of acetic acid in water]
Notes:
5-8% solution of acetic acid in water is called vinegar and is used widely as a preservative in pickles
12. What are the constituents of German Silver alloy?
[A] Gold, Aluminium and Copper
[B] Zinc, iron and Silver
[C] Bismuth, Antimony and Tin
[D] Copper, Nickel and Zinc
Show Answer
Correct Answer: D [Copper, Nickel and Zinc]
Notes:
German silver is a copper alloy with nickel and zinc. It is also known as Nickel silver or Maillechort. The usual composition is 60% copper, 20% nickel and 20% zinc.
13. Which of these is an ore of Aluminium?
[A] Corundum
[B] Kieserite
[C] Pitch blende
[D] All of the above
Show Answer
Correct Answer: A [Corundum]
Notes:
Corundum is an ore of Aluminium. It is a crystalline form of aluminium oxide. Kieserite is an ore of Magnesium and Pitch blende is an ore of Uranium.
14. What is the S.I unit of activity?
[A] becquerel
[B] curie
[C] candela
[D] henry
Show Answer
Correct Answer: A [becquerel]
Notes:
The SI unit for activity is becquerel, named after the discoverer of radioactivity, Henry Becquerel. The c.g.s unit of activity is curie.
15. Choose the correct statement about corrosion:
[A] Corrosion of metals is an electrochemical phenomenon
[B] Bisphenol can be used to cover the metal surface to prevent corrosion
[C] Both a and b
[D] None
Show Answer
Correct Answer: C [Both a and b]
Notes:
One of the simplest methods of to prevent corrosion is to prevent the surface of the metallic object to come in contact with atmosphere. This can be achieved by covering the surface with paint or by some chemicals (e.g. bisphenol).
16. Which of the following metals can easily be cut with a knife?
[A] Sodium
[B] Manganese
[C] Zinc
[D] Tin
Show Answer
Correct Answer: A [Sodium]
Notes:
Out of all the given options, Sodium is a softer metal and can be easily cut with a knife. It is a highly reactive metal which is silvery white in colour.
17. Which of the following is the main ingredient that is used to make cement?
[A] Calcium
[B] Silicon
[C] Aluminum
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Cement is manufactured through a closely controlled chemical combination of calcium, silicon, aluminum, iron and other ingredients. Common materials used to manufacture cement include limestone, shells, and chalk or marl combined with shale, clay, slate, blast furnace slag, silica sand, and iron ore.
18. Which of the following chemicals is used as a ‘fixer’ in photography?
[A] sodium sulphate
[B] sodium thiosulphate
[C] ammonium persulphate
[D] borax
Show Answer
Correct Answer: B [sodium thiosulphate]
Notes:
Fixation is commonly achieved by treating the film or paper with a solution of thiosulfate salt. Popular salts are sodium thiosulfate and ammonium thiosulfate. These are commonly used in modern rapid fixer formulae.
19. Which of the following is the working principle of a washing machine?
[A] Centrifugation
[B] dialysis
[C] reverse osmosis
[D] diffusion
Show Answer
Correct Answer: A [Centrifugation]
Notes:
The principle behind the spinning dry of the clothes in a washing machine is centrifugal force. The fast spinning around of the clothes in the drum creates a large centrifugal force from center to the edge of the drum, and the wet clothes are flung outwards to the drum edge and the water escapes through the drum holes.
20. Soft drinks such as colas contain significant quantities of?
[A] caffeine
[B] nicotine
[C] tannin
[D] renin
Show Answer
Correct Answer: A [caffeine]
Notes:
Soft drinks such as colas contain significant quantities of caffeine.
