Engineering Chemistry MCQ (Fibers)

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Engineering Chemistry MCQ (Fibers)

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Fibers – 1

1. The tensile strength of the fiber is ______________
a) Very Low
b) Low
c) High
d) Intermediate
Answer: c
Explanation: The tensile strength of the fiber is high and depends upon the strength
of the chemical bonds of the polymer chains.

2. Which of the following type of bonding maintains the alignment of chains of the polyester?
a) Vander Waal’s force
b) Dipole-dipole attraction
c) Hydrogen bonding
d) Covalent bonding
Answer: b
Explanation: Dipole-dipole attraction are induced due to the dipole formed by the
alignment of negative and positive charges and hence this type of bonding
maintains the alignment of chains of the polyester.

3. Nylon-66, PET and PAN all have Tg around ____________
a) 100 0C
b) 200 0C
c) 300 0C
d) 500 0C
Answer: a
Explanation: Nylon-66, PET and PAN all have Tg around 100 0C. The glass-transition
temperature Tg of a material characterizes the range of temperatures over which
this glass transition occurs. It is always lower than the melting temperature, of the
crystalline state of the material, if one exists.

4. Hydrogen bonding is responsible for maintaining the alignment of ____________
a) Stereoregular chains of isotactic polypropylene
b) Polyesters
c) Polyacrylonitrile
d) Polyamides
Answer: d
Explanation: Hydrogen bonding is responsible for maintaining the alignment of
polyamides and polyurethanes. Polyamides are polymer of a type made by the
linkage of an amino group of one molecule and a carboxylic acid group of another.

5. Nylon-6 can be prepared by ring opening polymerisation of ____________
a) Amino caproic acid
b) Caprolactum
c) Adipic acid
d) Terephthalic acid
Answer: b
Explanation: Nylon-6 can be prepared by ring opening polymerisation of
caprolactum. Caprolactum has 6 carbons and hence, Nylon-6.

6. Which of the following is the third step for the synthesis of nylon-6?
a) Conversion of cyclohexane into cyclohexanone
b) Ring opening polymerisation of caprolactum
c) Conversion of cyclohexanone-oxime into caprolactum
d) Conversion of cyclohexanone into cyclohexanone-oxime
Answer: c
Explanation: Conversion of cyclohexane into cyclohexanone is the initial step. Then
the second step is the conversion of cyclohexanone into cyclohexanone-oxime and
then the conversion of cyclohexanone-oxime into caprolactum is the third step for
the synthesis of nylon-6. Ring opening polymerisation of caprolactum is the last step.

7. The cyclohexanone is converted into cyclohexanone-oxime by ____________
a) Treatment with hydroxylamine
b) Oxidation
c) Reduction
d) Backmann rearrangement
Answer: a
Explanation: The cyclohexanone is converted into cyclohexanone-oxime by
treatment with hydroxylamine because hydroxylamine act as a catalyst for this
reaction. This is the second step for the synthesis of Nylon-6.

8. Nylon-6,6 is made by the condensation polymerisation of hexamethylene diamine and adipic acid in the molar ratio of ____________
a) 2 : 3
b) 1 : 2
c) 3 : 5
d) 1 : 1
Answer: d
Explanation: Nylon-6, 6 is made by the condensation polymerisation of
hexamethylene diamine and adipic acid in the molar ratio of 1 : 1. Equivalent
amounts of hexamethylene diamine and adipic acid are combined with water in a reactor.

9. The nylon-6, 6 have high crystallinity which imparts?
a) Low strength
b) Low meting point
c) Toughness and elasticity
d) Retention to poor mechanical properties
Answer: c
Explanation: The nylon-6, 6 have high crystallinity which imparts high strength, high
melting point, elasticity, toughness and retention to good mechanical properties.

10. Nylons are polar polymers and have good hydrocarbon resistance.
a) True
b) False
Answer: a
Explanation: Nylons are polar polymers and have good hydrocarbon resistance.
Nylon resins are widely used in the automobile industry especially in the engine
compartment.


Fibers – 2

1. Which of the following is not an application of nylon-6, 6?
a) Durable hair combs
b) Adhesives
c) Tyre cords
d) Medicine and pharmacy
Answer: b
Explanation: Durable hair combs, tyre cords, medicine and pharmacy are some of
the applications of nylon-6, 6.

2. Nylon-6, 6 have application in medicine and pharmacy because of ____________
a) Elasticity
b) Toughness
c) Good hydrocarbon resistance
d) Sterilisability
Answer: d
Explanation: Nylon-6, 6 have applications in medicine and pharmacy because of
sterilisability. It is also used as an engineering material in bearings and gears due to
its good abrasion resistance and self-lubricating properties.

3. The other name for dacron is ____________
a) Polyethylene terephthalate
b) Polyacrylonitrile
c) Polyamidenitrile
d) Polyethylene caprolactum
Answer: a
Explanation: The other name for dacron is polyethylene terephthalate. It is the most
common thermoplastic polymer resin of the polyester family and is used in fibers
for clothing, containers for liquids and foods.

4. PET is prepared by heating dimethyl terephthalate and ethylene glycol in ____________
a) Acidic medium
b) Basic medium
c) Neutral medium
d) Water
Answer: b
Explanation: PET is prepared by heating dimethyl terephthalate and ethylene glycol
in a basic medium at moderate pressure (2.7–5.5 bar) and high temperature (220–260 °C).

5. Terephthalic acid is converted into its dimethyl ester by treating it with ____________
a) Methyl chloride
b) Hydroxylamine
c) Methyl alcohol
d) Ethylene glycol
Answer: c
Explanation: Terephthalic acid is converted into its dimethyl ester by treating it with
methyl alcohol. At high temperature, TPA crystals constantly dissolve and reform
which increases the release of 4-formylbenzoic acid in solution where oxidation can be completed.

6. Blends of terylene fibers with wool have better crease and wrinkle resistance, they are more durable, higher strength, do not shrink and are not attacked by moths.
a) True
b) False
Answer: a
Explanation: Blends of terylene fibers with wool have better crease and wrinkle
resistance, they are more durable, higher strength, do not shrink and are not
attacked by moths. Terylene polyester staple fiber is being used in staple-fibre form
in blends with both natural and other synthetic fibers.

7. Which of the following is not an application of dacron?
a) Magnetic recording tapes
b) Wide-necked jars for coffee
c) Car heater
d) Window shades
Answer: d
Explanation: Magnetic recording tapes, wide-necked jars for coffee, car heater are
some of the applications of dacron.

8. Acrylonitrile is ____________
a) Vinyl chloride
b) Methyl alcohol
c) Methyl chloride
d) Vinyl cyanide
Answer: d
Explanation: Acrylonitrile is a vinyl cyanide. It is an organic compound with the
formula CH2CHCN and is colorless volatile liquid, although commercial samples can be yellow due to impurities.

9. Select the incorrect statement from the following option.
a) Orlon is the trade name of polyacrylonitrile
b) Orlon fibers are quick drying and resistant to water
c) Orlon fibers are less resistant to acid, gases than nylon
d) Orlon fibers are used for manufacturing window shades
Answer: c
Explanation: Orlon fibers are more resistant to acid, gases than nylon. All the other options are correct.

10. Polyacrylonitrile can be dissolved in its monomer so it can be shaped by bulk casting.
a) True
b) False
Answer: b
Explanation: Polyacrylonitrile does not dissolved in its monomer so it cannot be shaped by bulk casting.