Engineering Questions with Answers - Multiple Choice Questions

Applied Chemistry MCQ – Classification of Crude Oil based on their Composition

1 - Question

Paraffins are obtained by ______ process from petroleum.
a) fractional distillation
b) sedimentation
c) filtration
d) fermentation

View Answer

Answer: a
Explanation: Fractional distillation is the process in which the petroleum is refined and in this process at every stage there will some bi-product and at a certain stage paraffins are obtained in this process. Fermentation is used to produce the alcohol and filtration is the process of removing impurities.




2 - Question

Paraffins are mostly used as _______
a) dye
b) lubricant
c) catalyst
d) coolent

View Answer

Answer: b
Explanation: Paraffins are used as lubricant as it is having oily nature. Coolent is the substance which is used to cool down the system. In nuclear reactor water is used as coolent. Aniline is the example of dye.




3 - Question

Liquid paraffin is used as ________
a) Dye
b) Medical purposes
c) Inhibitor
d) Catalyst

View Answer

Answer: b
Explanation: The liquid paraffins are used for medical purposes. They are mainly used in ointments and gel type medicines.Inhibitor means negative catalyst.




4 - Question

What is the general formula for Naphthenes?
a) CnH2n+2
b) CnH2n
c) CnH2n-6
d) CnH2n-2

View Answer

Answer: b
Explanation: The general formula for Naphthenes is CnH2n. The general formula for paraffins CnH2n+2. The general formula for aromatics is CnH2n-6.




5 - Question

Naphthenes are also called as _______
a) cyclo alkanes
b) aromatics
c) cyclo alkenes
d) cyclo alkynes

View Answer

Answer: a
Explanation: Naphthenes can also be called as cyclo alkanes. Aromatics are mostly benzene rings.




6 - Question

Naphthenes having more than 20 C-atoms are called as ________
a) cyclo alkenes
b) cyclo alkanes
c) cyclo paraffins
d) cyclo alkynes

View Answer

Answer: c
Explanation: Cyclo paraffins are the Naphthenes having more than 20 C-atoms. The other cyclo compounds may have more than 20 carbon atoms but they are not Naphthenes.




7 - Question

Olefins are slightly soluble in ___________
a) water
b) alcohol
c) kerosene
d) ethanol

View Answer

Answer: a
Explanation: Olefins are slightly soluble in water. The branching increases the solubility of hydro carbons(Olefins).




8 - Question

 The chemical structure of Olefins can be given by ________
a) –(–CH2—CH2–)n
b)

--(--CH<sub>2</sub>---CH--)--
       I
       R

c) –(–CH2—CH–)n
d) –(–CH2—CH3–)n

View Answer

Answer: b
Explanation:

 

--(--CH<sub>2</sub>---CH--)--
       I
       R

is the structure of Olefins, where R is the amino
group. –(–CH2—CH2–)n— is the structure of ethylene.




9 - Question

Olefins containing 2 to 4 carbon atoms are ______ at ordinary temperature.
a) solid
b) liquid
c) gaseous
d) semisolid

View Answer

Answer: c
Explanation: The olefins containing 2 to 4 carbons are very small hydro carbons and they will be in gaseous state generally at room temperature.




10 - Question

Aromatic compounds are produced from ________
a) natural gas
b) coal tar
c) oil gas
d) heavy gas

View Answer

Answer: b
Explanation: Aromatic compounds are produced from coal tar. They are of fruity odor that means they will have some sweet smell.




11 - Question

Aromatic compounds are _____ with water.
a) dissolves
b) immiscible
c) forms lump
d) easily dissolves

View Answer

Answer: b
Explanation: Aromatic compounds do not dissolve in water. They do not form lumps with water but olefins will dissolve in water slightly.




12 - Question

The flame colour of the aromatic compounds is ________
a) yellow
b) orange
c) green
d) pink

View Answer

Answer: a
Explanation: The flame color of the aromatic compounds is in yellow as a lot of carbon in the compound changes into carbon black results in yellow flame.

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