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 among following is also known as white gold?
[A] Nickel
[B] Rhodium
[C] Platinum
[D] Palladium
Show Answer
Correct Answer: C [Platinum]
Notes:
Platinum is a naturally white metal. It doses not need to be alloyed for color. Due to its appearance as white, it is commonly known as White Gold.
2. Which among the following was the first artificially produced element?
[A] Neptunium
[B] Ununbium
[C] Technetium
[D] none of the above
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Correct Answer: C [Technetium]
Notes:
Technetium was the first artificially produced element. It was isolated by Carlo Perrier and Emilio Segrè in 1937. Technetium was created by bombarding molybdenum atoms with deuterons that had been accelerated by a device called a cyclotron.
3. PAN (Peroxyacetyl nitrate) is a secondary gaseous compound found in _?
[A] Classical smog
[B] Volatile organic compound
[C] Photochemical smog
[D] Green manure
Show Answer
Correct Answer: C [ Photochemical smog]
Notes:
Third option is the correct answer
Photochemical smog is the chemical reaction of sunlight, nitrogen oxides and volatile organic compounds in the atmosphere, which leaves airborne particles and ground-level ozone.
4. Which of the following chemicals is used as a molecular sieve to filter common salts from seawater to produce potable water?
[A] Graphene oxide
[B] Phosgene
[C] Sodium hypochlorite
[D] Calcium carbonate
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Correct Answer: A [ Graphene oxide]
Notes:
Graphene oxide is used as a molecular sieve to filter common salts from seawater to produce potable water.
5. What is dry ice?
[A] solidified form of Carbon dioxide
[B] frozen heavy water
[C] isotope of Hydrogen
[D] popular name of Benzene
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Correct Answer: A [solidified form of Carbon dioxide]
Notes:
Carbon dioxide can be obtained as a solid in the form of dry ice by allowing the liquified CO2 to expand rapidly.
6. Which of the following is correct about electrolytic refining?
[A] Strip of pure metal is used as anode
[B] Strip of pure metal is used as cathode
[C] Copper cannot be refined using an electrolytic method
[D] All of the above
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Correct Answer: B [Strip of pure metal is used as cathode]
Notes:
In electrolytic refining, the impure metal is made to act as anode. A strip of the same metal in pure form is used as cathode. Copper is generally refined using an electrolytic method.
7. Which of the following sub-atomic particle accompanies an electron emission in Beta–decay?
[A] antineutrino
[B] neutrino
[C] proton
[D] None of the above
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Correct Answer: A [antineutrino]
Notes:
The emission of electron in β−decay is accompanied by the emission of an antineutrino (ν ) and in β+ decay, a neutrino (ν) is generated.
8. Which of the following decays represents the decay of Uranium-238 to thorium-234?
[A] Alpha decay
[B] Beta decay
[C] Gamma decay
[D] None of the above
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Correct Answer: A [Alpha decay]
Notes:
The radioactive decay of uranium-238 to thorium-234, with the emission of a helium nucleus, is a well-known example of alpha decay.
9. What is the bond angle in case of Ammonia molecule?
[A] 120°
[B] 150°
[C] 66°
[D] 107°
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Correct Answer: D [107°]
Notes:
The bond angle in case of Ammonia molecule is 107° and the molecular geometry is trigonal pyramidal. The number of bond pairs in Ammonia is 3 and lone pair is 1.
10. What do we call the amount of energy required to break one mole of bonds of a particular type between two atoms in a gaseous state?
[A] Ionisation Potential
[B] Bond Enthalpy
[C] Electron affinity
[D] Bond order
Show Answer
Correct Answer: B [Bond Enthalpy]
Notes:
Bond Enthalpy is the amount of energy required to break one mole of bonds of a particular type between two atoms in a gaseous state. Its unit is KJ-1.
