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 substances is most suitable for making Compact Discs?
[A] PVC
[B] Polyethylene
[C] Polyamides
[D] Polycarbonates
Show Answer
Correct Answer: D [Polycarbonates
]
Notes:
Polycarbonate(PC) is a tough thermoplastic. It is not only highly transparent but also has good toughness which most of the other thermoplastics do not possess. For this reason, it is widely used for making CDs, Safety Goggles, Mixer jar lids etc.
2. Which of the following is not a common use of Graphite?
[A] Manufacturing of electrodes
[B] As a lubricant
[C] Manufacturing of crucibles
[D] In glass cutting
Show Answer
Correct Answer: D [In glass cutting]
Notes:
Graphite is renowned for its conspicuous uses owing to its unique properties like its ability to conduct electricity, which makes it ideal for electrode manufacturing. It’s also used as a lubricant and in the production of crucibles, thanks to its high melting point. However, it isn’t used in glass cutting.
3. The synthetic rubber Buna is obtained from the reaction of an unsaturated hydrocarbon with ___:
[A] Sodium
[B] Magnesium
[C] Potassium
[D] Lithium
Show Answer
Correct Answer: A [Sodium]
Notes:
Buna-S is a synthetic rubber formed by co-polymerization of a mixture of 1:3 butadiene and styrene. It is obtained from Sodium.
4. 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.
5. The largest component of Coal gas is__?
[A] Methane
[B] Hydrogen
[C] Carbon Dioxide
[D] Carbon Monoxide
Show Answer
Correct Answer: B [ Hydrogen]
Notes:
Typical composition of the Coal gas is as follows: •Hydrogen 50% •Methane 35% •Carbon monoxide 10% •Ethylene 5%
6. Which of the following element has the highest first ionization enthalpy?
[A] Magnesium
[B] Strontium
[C] Beryllium
[D] Barium
Show Answer
Correct Answer: C [Beryllium]
Notes:
The alkaline earth metals have low ionization enthalpies due to fairly large size of the atoms. Since the atomic size increases down the group, their ionization enthalpy decreases.
7. What is the general trend for ionization enthalpies of alkali metals as we move down the group?
[A] it increases
[B] it decreases
[C] it is same for all
[D] None
Show Answer
Correct Answer: B [it decreases]
Notes:
The ionization enthalpies of the alkali metals are considerably low and decrease down the group from Li to Cs.
8. What is the hemihydrate of calcium sulphate commonly known as?
[A] Gypsum
[B] Plaster of Paris
[C] Chloroform
[D] Limestone
Show Answer
Correct Answer: B [Plaster of Paris]
Notes:
Plaster of Paris is the common name of calcium sulphate hemihydrate because half molecule of water is attached with calcium sulphate. The chemical formula of plaster of Paris is CaSO4.1/2H2O.
9. Which of the following compounds is manufactured using the Contact Process?
[A] Sulphuric Acid
[B] Nitric Acid
[C] Hydrochloric Acid
[D] Benzene
Show Answer
Correct Answer: A [Sulphuric Acid]
Notes:
The Contact Process is a method primarily used for preparing sulphuric acid on a large scale. It involves the oxidation of sulfur dioxide to sulfur trioxide in presence of a catalyst such as vanadium pentoxide. The subsequent hydration of sulfur trioxide produces sulphuric acid. The Contact Process allows the production of high concentrations of sulphuric acid under economically feasible conditions.
10. Which of the following is NOT correct about Ethanol?
[A] It is a good solvent
[B] It gives out hydrogen when reacted with Sodium
[C] It is an odorless liquid
[D] All are correct
Show Answer
Correct Answer: C [It is an odorless liquid]
Notes:
Ethanol is a good solvent and reacts with sodium leading to the evolution of hydrogen. It is a colorless liquid with a slight characteristic odor.
