This set of Engineering Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “Polymer Classification”.
1. A polymer is any substance made up of many repeating units called ______________
a) Resins
b) Plastic
c) Mers
d) Blocks
View Answer
Explanation: A polymer is any substance made up of many repeating units, building blocks called mers. Polymers are made up of many many molecules all strung together to form really long chains.
2. Small molecules which combine to form polymer are called ____________
a) Resins
b) Monomers
c) Plastic
d) Blocks
View Answer
Explanation: Small molecules which combine with each other to form polymer are called monomers. Polymers are made up of many many molecules all strung together to form really long chains.
3. Select the incorrect statement from the following options.
a) When in form ready for further working, polymers are called resins
b) The chemical process leading to the formation of polymer is known as polymerisation
c) The number of monomeric units contained in the polymer is called the degree of polymerisation
d) Due to their small size, polymers are also called micro-molecules
View Answer
Explanation: Due to their large size, polymers are also called macro-molecules. All the other options are correct. When in form ready for further working, polymers are called resins. The chemical process leading to the formation of polymer is known as polymerisation and the number of monomeric units contained in polymer is called degree of polymerisation.
4. Below threshold degree of polymerisation (DP), the polymer does not possess any strength and exist either as liquid resin or friable powder.
a) True
b) False
View Answer
Explanation: Below threshold degree of polymerisation, the polymer does not possess any strength and exist either as liquid resin or friable powder. The number of monomeric units contained in the polymer is called degree of polymerisation.
5. The optimum DP value of cellulose is ____________
a) 150
b) 250
c) 400
d) 500
View Answer
Explanation: The optimum DP value of cellulose is 250. The number of monomeric units contained in the polymer is called degree of polymerisation (DP).
6. The functionality of ethylene glycol is ____________
a) 2
b) 3
c) 4
d) 5
View Answer
Explanation: The functionality of ethylene glycol is 2. It is a colorless, odorless, viscous dihydroxy alcohol and has a sweet taste, but is poisonous if ingested.
7. Which of the following polymer is not classified under the category of configuration?
a) Syndiotactic
b) Atactic
c) Cross-linked
d) Isotactic
View Answer
Explanation: Cross-linked polymer is not classified under the category of configuration. Syndiotactic, atactic and isotactic are classified under the category of configuration. Tacticity is the relative stereochemistry of adjacent chiral centers within a macromolecule.
8. Which of the following is not an example of semi-crystalline polymer?
a) HDPE
b) Nylon
c) Polyesters
d) LDPE
View Answer
Explanation: LDPE is not an example of a semi-crystalline polymer. It is an example of a branched amorphous polymer. All the other options are examples of semi-crystalline polymer.
9. Styrene acrylonitrile is an example of ____________
a) Co-polymer
b) Homopolymer
c) Linear polymer
d) Amorphous polymer
View Answer
Explanation: Styrene acrylonitrile resin is a copolymer plastic consisting of styrene and acrylonitrile. It is also known as SAN. It is widely used in place of polystyrene.
10. Which of the following polymer is not classified under the category of end use?
a) Fibers
b) Adhesives
c) Elastomers
d) Synthetic
View Answer
Explanation: Synthetic polymer is not classified under the category of end use. It is classified under the category of origin. Fibers, adhesives and elastomers are classified under the category of end use.
11. Select the incorrect statement from the following option.
a) Thermosets are formed by condensation polymerisation reactions
b) Thermosets have 3-D, cross-linked network structure
c) Thermosets soften on heating and stiffen on cooling
d) Thermosets are generally insoluble in any solvent
View Answer
Explanation: Thermosets do not soften on heating. All the other options are correct. Thermosets are formed by condensation polymerisation reactions, have 3-D, cross-linked network structure and are generally insoluble in any solvent.
12. Which one of the following is not an example of thermoplastic?
a) Polyvinyl chloride
b) Nylon
c) Polyesters
d) Epoxy
View Answer
Explanation: Epoxy is not an example of thermoplastic. It is an example of a thermoset polymer. Polyvinyl chloride, nylon and polyesters are examples of thermoplastic.
13. The weight average molecular weight for PP given its degree of polymerisation as 10,000 will be ____________
a) 3,00,000 gm/mol
b) 4,20,000 gm/mol
c) 6,70,000 gm/mol
d) 8,40,000 gm/mol
View Answer
Explanation: The weight average molecular weight for PP given its degree of polymerisation as 10,000 will be 4,20,000 gm/mol.
14. The cryoscopy refers to ____________
a) Osmotic pressure measurement
b) Elevation in boiling point measurement
c) Freezing point depression measurement
d) Increase in solubility measurement
View Answer
Explanation: The cryoscopy refers to freezing point depression measurement. A technique for determining the molar concentration of a solution by measuring the freezing point.
15. Higher molecular weight polymers are tougher and more heat resistant.
a) True
b) False
View Answer
Explanation: Higher molecular weight polymers are tougher and more heat resistant. Polymeric mixtures are far less miscible than mixtures of small molecule materials.
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