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 the following compound is most commonly used in the Photochromic lenses?
[A] Potassium Dichromate
[B] Silver Chloride
[C] Potassium ferrate
[D] Ferric Chloride
Show Answer
Correct Answer: B [Silver Chloride]
Notes:
Photochromatic or Photochromic glass acquires a darker shade when exposed to bright light and returns to its original lighter shade in dim light. This happens because silver halides (iodide or chloride) is added to this glass
2. The term “white coal” sometimes referred to which of the following?
[A] Geothermal Electricity
[B] Wind Energy
[C] Hydroelectricity
[D] Biomass Energy
Show Answer
Correct Answer: C [Hydroelectricity]
Notes:
The term white coal was used for Hydroelectricity, particularly in Europe, because of its capability to produce more energy than any other source except coal. The term was coined by a French Engineer Aristide Bèrges.
3. Carnotite is a mineral of which among the following metals?
[A] Lead
[B] Uranium
[C] Aluminium
[D] Iron
Show Answer
Correct Answer: B [Uranium]
Notes:
Carnotite is an ore of Uranium and comprises potassium, vanadium, water and few other elements such as calcium, barium, magnesium, iron, sodium etc. It is a yellow colored mineral.
4. How does the Isotope of Iodine, Iodine-135 plays an important role in Nuclear Power Generation?
[A] It is used as a fuel supplement in some of the modern Nuclear Reactors
[B] It is a bi-product of Nuclear Reaction which kills the neutrons and this inhibits the power formation
[C] It is a moderator used actively in the Nuclear Reactors
[D] It is an experimental substance for Nuclear Fusion
Show Answer
Correct Answer: B [It is a bi-product of Nuclear Reaction which kills the neutrons and this inhibits the power formation]
Notes:
Iodine-135 is a important by-product of nuclear fission, particularly in reactors using uranium fuel. It has a high neutron capture cross-section, meaning it effectively absorbs neutrons, which can inhibit the fission process and reduce reactor power output. This property makes it crucial for managing reactor control and safety, as its presence can lead to a phenomenon known as “neutron poison,” affecting the overall efficiency of the nuclear reaction.
5. Ground Level Ozone is formed due to reaction between:
[A] VOCs, Oxides of Nitrogen & Sunlight
[B] VOCs, Sulphur dioxide & Sunlight
[C] Ozone, Sulphur dioxide & Oxides of Nitrogen
[D] Ozone, Oxides of Nitrogen & Sunlight
Show Answer
Correct Answer: A [VOCs, Oxides of Nitrogen & Sunlight]
Notes:
Ground Level Ozone results from photochemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOCs) in the presence of sunlight.
6. Which of the following is not an isotope of Hydrogen?
[A] Protium
[B] Para hydrogen
[C] Deuterium
[D] Tritium
Show Answer
Correct Answer: B [ Para hydrogen]
Notes:
The three most stable isotopes of hydrogen: Protium, Deuterium and Tritium. Para hydrogen is not an isotope of hydrogen. Molecules of hydrogen in which the spins of both the nuclei are in the opposite direction are called Para hydrogen.
7. How is Aqua regia formed?
[A] by mixing 2 parts of concentrated HCl and one part of concentrated HNO3
[B] by mixing 3 parts of concentrated HCl and one part of concentrated HNO3
[C] by mixing 1 part of concentrated HCl and three parts of concentrated HNO3
[D] None of the above
Show Answer
Correct Answer: B [by mixing 3 parts of concentrated HCl and one part of concentrated HNO3]
Notes:
When three parts of concentrated HCl and one part of concentrated HNO3 are mixed, aqua regia is formed which is used for dissolving noble metals, e.g., gold, platinum.
8. Which of the following defines the solubility of a solution?
[A] amount of the solvent present in the saturated solution
[B] amount of the solute present in the saturated solution
[C] amount of the solute per amount of solute in the solution
[D] difference of amount of solvent and the amount of solute
Show Answer
Correct Answer: B [amount of the solute present in the saturated solution]
Notes:
The amount of the solute present in the saturated solution at a given temperature is called its solubility.
9. Which of these methods is suitable to obtain the coloured component from black ink?
[A] Evaporation
[B] Sublimation
[C] Crystallisation
[D] All of the above
Show Answer
Correct Answer: A [Evaporation]
Notes:
The dye from water can be separated by the method of evaporation. Evaporation is used to separate the volatile component (solvent) from its non-volatile solute.
10. 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
Show Answer
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.
