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 method will is most suitable to separate the mixture of ammonium chloride and salt?
[A] Evaporation
[B] Sublimation
[C] Simple Distillation
[D] All of the above
Show Answer
Correct Answer: B [Sublimation]
Notes:
Sublimation is the property of substance in which they are converted directly from solid to gas or vice versa. Ammonium chloride is a sublime solid.
12. Which of the following is the correct order of the decreasing order of abundance of the elements in earth’s crust?
[A] Iron > Silicon > Oxygen >Aluminium
[B] Oxygen > Silicon > Aluminium > Iron
[C] Oxygen> Iron > Aluminium > Silicon
[D] Iron > Aluminium > Silicon > Oxygen
Show Answer
Correct Answer: B [Oxygen > Silicon > Aluminium > Iron]
Notes:
Oxygen is the most abundant element in the earth’s crust followed by Silicon, Aluminium and Iron. It comprises almost half of the mass of the earth’s crust.
13. Which of the following molecules have a T-shape arrangement?
[A] Ozone
[B] Water
[C] Chlorine Trifluoride
[D] Sulphur dioxide
Show Answer
Correct Answer: C [Chlorine Trifluoride]
Notes:
Chlorine trifluoride has 10 electrons around the central chlorine atom. There are five electron pairs arranged in a trigonal bipyramidal shape and two equatorial lone pairs making the final structure T-shaped.
14. What is the product when Methane reacts with steam in the presence of Nickel catalyst?
[A] Carbon dioxide and ethane
[B] Ethyne
[C] Carbon monoxide and dihydrogen
[D] Carbon monoxide and Water vapour
Show Answer
Correct Answer: C [Carbon monoxide and dihydrogen]
Notes:
Methane reacts with steam at 1he temperature of 273 K in the presence of nickel catalyst to form carbon monoxide and dihydrogen. This method is used for industrial preparation of dihydrogen gas.
15. Which of these polymers are used to produce Butyl-rubber?
[A] butadiene and neoprene
[B] butadiene and styrene
[C] butadiene and acrylonitrile
[D] butadiene and isobutylene
Show Answer
Correct Answer: D [butadiene and isobutylene]
Notes:
Butyl-rubber is a synthetic rubber which is obtained as a result of co-polymerization of butadiene and isobutylene.
16. What is the monomer unit of PMMA?
[A] butyl methacrylate
[B] ethyl methacrylate
[C] methyl methacrylate
[D] iso-propyl methacrylate
Show Answer
Correct Answer: C [methyl methacrylate]
Notes:
The monomer unit of PMMA is methyl methacrylate. It is a hard and transparent polymer and quite resistant to the effect of heat, light and ageing. It has high optical clarity.
17. 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.
18. Which of these non-metals finds its use as a diluent for oxygen in modern diving apparatus?
[A] Neon
[B] Helium
[C] Bromine
[D] Argon
Show Answer
Correct Answer: B [ Helium ]
Notes:
Helium is used as a diluent for oxygen in modern diving apparatus because of its very low solubility in blood. Helium is a non-inflammable and light gas.
19. Which of these chemicals is used as a water softening agent?
[A] Baking soda
[B] Washing soda
[C] Bleaching powder
[D] Slaked lime
Show Answer
Correct Answer: B [Washing soda]
Notes:
Washing soda’s chemical formula is Na2CO3. It binds calcium and magnesium present in the water and creates an insoluble substance.
20. Which of these chemical is used to form soaps containing sodium salts?
[A] Sulphuric acid
[B] Sodium hydroxide
[C] Nitric acid
[D] Carbonic acid
Show Answer
Correct Answer: B [Sodium hydroxide]
Notes:
Soaps containing sodium salts are formed by heating fat with aqueous sodium hydroxide solution. This reaction is known as saponification.
