This set of Engineering Chemistry Interview Questions and Answers focuses on “Thermoplastic Polymers – 2”.
1. Which of the following act as a catalyst in the preparation of PVC?
a) Lewis acid
b) Benzoyl peroxide
c) Potassium amide
d) Grignard reagent
View Answer
Explanation: Benzoyl peroxide act as a catalyst in the preparation of PVC. The product of the polymerization process is unmodified PVC.
2. Select the incorrect statement from the following option.
a) PVC is colourless, odourless and non-inflammable
b) PVC has poor oil resistance and resistance to weathering
c) PVC is used for making bottles for consumable liquids
d) PVC has superior chemical resistance but is soluble in ethyl chloride
View Answer
Explanation: PVC has excellent oil resistance and resistance to weathering. It is colorless, odourless and non-inflammable and is used for making bottles for consumable liquids. PVC has poor oil resistance and resistance to weathering.
3. The C-Cl dipole makes PVC a polymeric polar molecule.
a) True
b) False
View Answer
Explanation: The C-Cl dipole makes PVC a polymeric polar molecule.PVC has excellent oil resistance and resistance to weathering. It is colorless, odourless and non-inflammable.
4. Plasticized PVC is not used for making ____________
a) Baby-pants
b) Bathroom curtaining
c) Pipes for drainage
d) Garden hose
View Answer
Explanation: Plasticised PVC is not used for making pipes for drainage. It is used for making baby-pants, bathroom curtaining and garden hose.
5. Which of the following is also known as lucite?
a) Teflon
b) Polyvinyl acetate
c) Polystyrene
d) Perspex
View Answer
Explanation: Perspex is also known as lucite. It is a solid transparent plastic made of polymethyl methacrylate.
6. Which of the following is used for making chewing gums?
a) Perspex
b) Polyvinyl acetate
c) Teflon
d) Polystyrene
View Answer
Explanation: Polyvinyl acetate is used for making chewing gums. It is also used in handicrafts, envelope and wallpaper adhesives.
7. Which of the following statement is incorrect about the Teflon?
a) It has high density of the order 2.1 to 2.3 gm/cm3
b) It has excellent electrical insulation properties
c) It has high coefficient of friction
d) It is dense and chemically inert
View Answer
Explanation: Teflon has very low coefficient of friction. All the other options are correct.
8. Which of the following is an application of Teflon?
a) Coatings of frying pans
b) Combs and brush handles
c) Audio cassettes
d) Optical fibres
View Answer
Explanation: Coatings of frying pans, non-lubricating bearings, wire and cable insulation etc are some of the applications of Teflon. it is also used as liners in hose assembly.
9. Polystyrene is prepared by ___________ polymerisation of styrene.
a) Condensation
b) Free radical
c) Anionic
d) Cationic
View Answer
Explanation: Polystyrene is prepared by free radical polymerisation of styrene in the presence of benzoyl peroxide as catalyst.
10. The softening temperature of polystyrene is ____________
a) 10-20 0C
b) 30-50 0C
c) 80-100 0C
d) 120-150 0C
View Answer
Explanation: The softening temperature of polystyrene is 80-100 0C. Polystyrene is a vinyl polymer. Structurally, it is a long hydrocarbon chain, with a phenyl group attached to every other carbon atom.
11. Due to the chain stiffening effect of a benzene ring, polystyrene is hard but brittle.
a) True
b) False
View Answer
Explanation: Due to chain stiffening effect of a benzene ring, polystyrene is hard but brittle. Polystyrene is also used for producing disposable plastic cutlery and dinnerware
12. Which of the following is an application of polystyrene?
a) Insulators for motors
b) Dome-shaped covers for solar collectors
c) Laminates for printed circuitry
d) Containers for talcum powder
View Answer
Explanation: Containers for talcum powder, combs and brush handles, audio cassettes etc are some of the applications of polystyrene. But it is not used as insulators for motors or covers for solar collectors.
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