Assertion and Reason Based on Polymers Class 12 Chemistry Chapter 15
Directions: These questions consist of two statements, one is Assertion and other is Reason. While answering these questions, you have to choose any one of the following four responses.
(a) If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
(b) If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
(c) If the Assertion is correct but Reason is incorrect.
(d) If the Assertion is incorrect but Reason is correct.
1. Assertion: Olefinic monomers undergo addition polymerisation.
Reason: Polymerisation of vinylchloride is initiated by peroxides/ persulphates.
Answer
a2. Assertion: Teflon has high thermal stability and chemical inertness.
Reason: Teflon is a thermoplastic.
Answer
(b)3. Assertion: Bakelite is a thermosetting polymer.
Reason: Bakelite can be melted again and again without any change.
Answer
(c)4. Assertion: In vulcanisation of rubber, sulphur cross links are introduced.
Reason: Vulcanisation is a free radical initiated chain reaction.
Answer
(b)5. Assertion: The time of vulcanisation and temperature is increased by adding accelerators.
Reason: By vulcanising, a material of high tensile strength can be obtained.
Answer
(d)6. Assertion: Most of the Synthetic polymers are not biodegradable.
Reason: Polymerisation process induces toxic character in organic molecules.
Answer
(c)7. Assertion: Low density polythene is used in the insulation of electricity carrying wires.
Reason: Low density polythene is chemically inert and tough.
Answer
Answer: (b)8. Assertion: Zeigler-Natta catalyst is a mixture of triethylaluminium and titanium tetrachloride.
Reason: Zeigler-Natta catalyst is used to make low density polythene.
Answer
Answer: (c)9. Assertion: PTFE has high thermal stability and chemical inertness.
Reason: It is a thermoplastic.
Answer
Answer: (b)10. Assertion: Polyamides are best used as fibres because of high tensile strength.
Reason: Strong intermolecular forces (like hydrogen bonding within polyamides) lead to close packing of chains and increase the crystalline character, hence provide high tensile strength to polymers.
Answer
Answer: (a)11. Assertion: 5% of sulphur is added to natural rubber for manufacturing tyre tubes.
Reason: It acts as a cross linking agent and thus makes the rubber stiffer.
Answer
Answer: (a)12. Assertion: Network polymers are thermosetting.
Reason: Network polymers have high molecular mass.
Answer
Answer: (b)13. Assertion: Ordinary rubber is an elastomer.
Reason: The intermolecular forces of attraction between the polymer chains are weak vander Waals’ forces.
Answer
Answer: (a)14. Assertion: Rayon is a semi synthetic polymer and is taken as a better choice than cotton fabric.
Reason: Mechanical and aesthetic properties of cellulose can be improved by acetylation.
Answer
Answer: (b)15. Assertion:Cotton is a polymer
Reason:A polymer is a very big molecule made of many small repeating units of compounds called monomers.
Answer
Answer: (b)16. Assertion: Polytetrafluoroethene is used in making non-stick cookwares.
Reason: Fluorine has highest electronegativity.
Answer
Answer: (b)17. Assertion: Phenol-Formaldehyde polymer is a thermosetting polymer.
Reason: It can be melted time and again without any change.
Answer
Answer: (c)18. Assertion: For making rubber synthetically, isoprene molecules are polymerised.
Reason: Neoprene (a polymer of chloroprene) is a synthetic rubber.
Answer
Answer: (d)19. Assertion: Network polymers are thermosetting.
Reason:Network polymers have a high molecular mass.
Answer
Answer: (b)20.Assertion: Elastomers can be stretched.
Reason: The intermolecular force in these polymers is very strong.
Answer
Answer: (c)21.Assertion: Cationic addition polymerization is facilitated in monomers containing electron releasing groups.
Reason: The electron releasing groups stabilize the intermediate cation.
Answer
Answer: (a)22.Assertion: The monomer containing nitrile groups usually undergo anionic addition polymerization.
Reason: -CN group is an electron-withdrawing group and stabilizes the intermediate anion.
Answer
Answer: (c)23.Assertion: Polybutadiene is an example of chain growth polymer.
Reason: In chain growth polymers, the reactive particles may be free radicals or ions (cations or anions) to which monomers get added by a chain reaction.
Answer
Answer: (a)24.Assertion: Polymerides are bust used as fiber because of high tensile strength.
Reason: Strong intermolecular forces (like hydrogen bonding within polyamides) lead to close tracking of chains and increase the crystalline character, hence, provide high tensile strength to polymers.
Answer
Answer: (a)25.Assertion: The Vulcanized rubber has greater elasticity and tensile strength than crude rubber.
Reason: In vulcanized rubber, cross-links are developed
Answer
Answer: (a)26.Assertion: The gross mobility of elastomer chain is due to its special characteristics.
Reason: It contains network of cross-links
Answer
Answer: (a)27.Assertion: Novalac is heated in presence of hex- amethylene-tetra amine to form hard bakelite.
Reason: This heating forms a straight-linked three-dimensional polymeric arrangement.
Answer
Answer: (c)
28.Assertion: The polymerization of propylene is carried out in the presence of SnCl2 and triethyl aluminium.
Reason: SnCl4 and triethyl aluminium acts as the catalyst in the polymerization reaction.
Answer
Answer: (d)29.Assertion: Most of the polymeric materials are non-biodegradable.
Reason: The use of polymeric materials is increasing due to low cost and variable applications.
Answer
Answer: (b)30.Assertion: Polybutadiene is an example of chain growth polymer.
Reason: In chain growth polymers, the reac- tive particles may be free radicals or ions (cations or anions) to which monomers get added by a chain reaction.
Answer
Answer: (a)Class-11
Class-12
