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 not a correct statement about Bitumen?
[A] It’s a mixture of highly condensed polycyclic aromatic compounds
[B] Its is soluble in Carbon Disulphide
[C] SARA analysis is used to determine bitumen chemistry
[D] All of above are correct statements
Show Answer
Correct Answer: D [ All of above are correct statements ]
Notes:
Bitumen is a mixture of organic liquids that are highly viscous, black, sticky, soluble in carbon disulfide and composed of highly condensed polycyclic aromatic hydrocarbons.
2. Dalton’s name is associated with which of the following terms?
[A] Electron
[B] Proton
[C] Atom
[D] Neutron
Show Answer
Correct Answer: C [Atom]
Notes:
John Dalton introduced the atomic theory into chemistry. The main points of Dalton’s atomic theory are (1) Elements are made of extremely small particles called atoms. (2) Atoms of a given element are identical in size, mass and other properties; atoms of different elements differ in size, mass and other properties.(3) Atoms cannot be subdivided, created or destroyed. (4) Atoms of different elements combine in simple whole-number ratios to form chemical compounds. (5) In chemical reactions, atoms are combined, separated or rearranged.
3. Which of the following is not a non-metallic mineral?
[A] Mica
[B] Bauxite
[C] Granite
[D] Silica
Show Answer
Correct Answer: B [Bauxite]
Notes:
Non-metallic minerals are those minerals which do not contain metals. Examples of Non-Metallic minerals include limestone, mica, coal, gypsum, dolomite, phosphate, salt, granite etc.
4. Which of the following is an anti-knocking compound that has been phased out in many countries so far?
[A] Lead tetrachloride
[B] Tetra Ethyl Lead
[C] Ethyl acetate
[D] None of the above
Show Answer
Correct Answer: B [Tetra Ethyl Lead ]
Notes:
Tetra Ethyl Lead (TEL) is one such component that is added to petrol to reduce its tendency to `ping’ under compression. TEL breaks down to lead at upper cylinder temperatures. Lead atoms spread around and combining with the free radicals and slowing down the reaction.
However, `Leaded’ petrol was a grave danger to the environment, as lead is a poison when it is absorbed into the body.
5. What type of fiber is Rayon considered?
[A] A synthetic fiber
[B] A natural fiber
[C] A semi-synthetic fiber
[D] A synthetic detergent
Show Answer
Correct Answer: C [A semi-synthetic fiber]
Notes:
Rayon is considered a semi-synthetic fiber. It is made by regenerating natural materials into a usable form. Rayon fibers are derived from cellulose obtained from wood or related agricultural products. It was first commercially produced in 1905 by the Swiss firm J. R. Geigy, originally under the name “artificial silk”
6. What is Carbamide?
[A] A Pesticide
[B] A Fertilizer
[C] A Textile Dye
[D] An Explosive
Show Answer
Correct Answer: B [A Fertilizer]
Notes:
Carbamide is another name of Urea, an organic compound with chemical formula CO(NH2)2. This name indicates that Urea is an amide in which two –NH2 groups are joined by a carbonyl (C=O) functional group.
7. 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.
8. What is the reason for the increase in the electronegativity across a period from left to right?
[A] attraction between the valence electrons and the nucleus increases
[B] attraction between the valence electrons and the nucleus decreases
[C] increase in the atomic weight
[D] None of the above
Show Answer
Correct Answer: A [attraction between the valence electrons and the nucleus increases]
Notes:
The attraction between the outer (or valence) electrons and the nucleus increases as the atomic radius decreases in a period. The electronegativity also increases.
9. In which of the following groups is Gold placed in the modern periodic table?
[A] 10
[B] 12
[C] 11
[D] 9
Show Answer
Correct Answer: C [11]
Notes:
Gold, with the atomic number of 79 is classified under group 11 of the modern periodic table. This group also contains silver and copper and is often referred to as the coinage metals due to their historical use in coins. They are known for their high electrical conductivity, resistance to tarnish, and are extremely malleable and ductile.
10. What do we call the covalent bond where the electrons of the shared pair are contributed by only one species?
[A] Polar Covalent bonds
[B] Coordination Covalent bonds
[C] Unilateral Covalent bonds
[D] None of the above
Show Answer
Correct Answer: B [Coordination Covalent bonds]
Notes:
The covalent bond where the electrons of the shared pair are contributed by only one species are called as Coordination Covalent bonds or Dative bonds. The common example is the formation of a bond between boron trifluoride (BF3) and ammonia (NH3).
