General Science Chemistry MCQs
Chemistry Objective (Multiple Choice) General Knowledge Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examination
61. What do we call the number of water molecules present in one formula unit of a salt?
[A] Formula number of salt
[B] Power of the salt
[C] Water of crystallisation
[D] Hydro number
Show Answer
Correct Answer: C [Water of crystallisation]
Notes:
The fixed number of water molecules present in one formula unit of a salt is called water of crystallisation. For example, one formula unit of copper sulphate has five molecules of water in it.
62. Which of the following is the formula of cell constant?
[A] length/2 x Area
[B] length/Area
[C] 2 x length/Area
[D] length x Area
Show Answer
Correct Answer: B [length/Area]
Notes:
The quantity length/Area is called cell constant denoted by the symbol, G*. The cell constant is usually determined by measuring the resistance of the cell containing a solution whose conductivity is already known.
63. Which of the following is / are correct statements with respect to Graphite?
- It is the most stable phase of carbon at normal conditions
- It is made of made of sp3 hybridized carbon atoms
- It is good conductor of both heat and electricity
Select the correct option from the codes given below:
[A] Only 1 & 2
[B] Only 2 & 3
[C] Only 1 & 3
[D] 1, 2 & 3
Show Answer
Correct Answer: C [Only 1 & 3 ]
Notes:
Graphite is an allotrope of Carbon. It is a good conductor of electricity as well as heat. It is also most stable phase of carbon at normal conditions. It is made of made out of sp2 hybridized carbon atoms.
64. Which of these alkanes has higher boiling point?
[A] Butane
[B] Methane
[C] Ethane
[D] Hexane
Show Answer
Correct Answer: D [Hexane]
Notes:
There is a steady increase in boiling point with the increase in molecular mass. This is due to the fact that the intermolecular van der Waals forces increase with increase of the molecular size or the surface area of the molecule.
65. Which of the following represents the mixture of carbon monoxide and nitrogen?
[A] Coal tar
[B] Producer gas
[C] Water gas
[D] All of the above
Show Answer
Correct Answer: B [Producer gas]
Notes:
Producer gas is a mixture of carbon monoxide and nitrogen. Producer gas is produced by passing air over red-hot coke. Coke is also used in the production of producer gas.
66. Which of the following is a property of Alkanes?
[A] Alkanes are unreactive at normal conditions
[B] Alkanes are also known as Paraffins
[C] Both a and b
[D] None
Show Answer
Correct Answer: C [Both a and b]
Notes:
Alkanes are inert under normal conditions as they do not react with acids, bases and other reagents. They are also known as paraffins.
67. Which of the following alkene shows structural isomerism?
[A] Ethene
[B] Propene
[C] Butene
[D] All of the above
Show Answer
Correct Answer: C [Butene]
Notes:
Ethene and propene can have only one structure but alkenes higher than propene have different structures. For example: But-1-ene and But-2- ene.
68. Which of the following is an example of a Thermosetting plastic?
[A] Melamine
[B] Bakelite
[C] Formaldehyde resin
[D] Teflon
Show Answer
Correct Answer: D [Teflon]
Notes:
A Thermosetting polymer can be heated only once when it permanently sets into a solid which can not be remelted and remoulded. The thermosetting plastic is cross linked and is permanently rigid. The common example are bakelite, melamine, formaldehyde resin, etc. Teflon is a thermoplastic.
69. What is the monomer unit of Teflon?
[A] Acetylene
[B] terafluoroethylene
[C] neoprene
[D] Propylene
Show Answer
Correct Answer: B [terafluoroethylene]
Notes:
The monomer unit of Teflon is terafluoroethylene molecule. Teflon is prepared by heating tetra fluoroethylene under pressure in the presence of ammonium peroxosulphate.
70. Which of the following polymer is obtained by the condensation reaction between ethylene glycol and terephthalic acid?
[A] Terelene
[B] PMMC
[C] PVC
[D] None of the above
Show Answer
Correct Answer: A [Terelene]
Notes:
Terelene is a polymer obtained by the condensation reaction between ethylene glycol and terephthalic acid. It is widely used in making wash and wear fabrics as it has low absorbing power.
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