Q.1 Give examples of semi synthetic polymers.
Answer: Cellulose acetate (rayon) and cellulose nitrate.
Q.2 Which type of polymer nylon-6.6, is ?
Answer: Polymide polymer or (condensation polymer).
Q.3 Give example of thermoplastic.
Answer: Polythene, polystyrene and polyvinyl.
Q.4 Give the name of monomer ofnylon-2, nylon-6.
Answer: Glycine and amino caproic acid.
Q.5 What is the significance of number 6,6 and 6 in nylon-6,6 and nylon-6?
Answer: In monomer of nylon-6,6 (hexamethylene demine and atopic acid) 6,6 refers to number of carbon atoms. Both have six carbon atoms. In nylon-6, monomer is caprolactum which has also six carbon atoms.
Q.6 What is novolac?
Answer: The initial product formed when phenol and formaldehyde are polymerised is novolac.
Q.7 What is bakelite?
Answer: Bakelite is a thermosetting polymer of phenol and formaldehyde.
Q.8 Which type of polyesters are biodegradable?
Answer: Aliphatic polyesters.
Q.9 Name the polymer used in the insulation of electrical wire.
Answer: Styrene-Butadiene copolymer. (SBR or Buna-S)
Q.10 Name the polymer used in making non-stick kitchen wares.
Q.11 Name a polymer used as a substitute for wool.
Answer: PAN (Poly acrylonitrile) or orlon.
Q.12 Name a polymer used in making unbreakable crockery.
Answer: Melamine-formaldehyde co-polymer.
Q.13 Name the polymer used in making C.D.
Answer: Polystyrene and polycarbonates.
Q.14 Name a polymer used in the manufacture of paints and lacquers.
Q.15 Name the monomer of (a) PHBV and (b) Nylon-2, Nylon-6.
Answer: (a) 3-Hydroxy butanoic acid and 3-Hydroxy pentanoic acid. (b) Glycine and amino caproic acid.
Q.16 Name the catalyst used in free radical addition polymerization as initiator.
Answer: Benzoyl peroxide.
Q.17 Name the catalyst used in the preparation of high density polythene.
Answer: Triethyl aluminium and titanium tetrachloride (Zieeler Natta catalyst).
Q.18 Name the catalyst used in the preparation of low density polythene.
Answer: Traces of dioxygen or peroxide initiator.
Q.19 What is difference between novolac and bakelite?
Answer: The initial linear product formed by the polymerisation of phenol and formaldehyde is called novolac. It is soft. Whereas novolac on heating with formaldehyde undergoes cross linking to form bakelite. It is hard.
Q.20 What percentage of sulphur is used to obtain tyre rubber from natural rubber?
Answer: 5% sulphur is used to obtain tyre rubber.
Q.21 What is the role of sulphur in the vulcanisation of rubber?
Answer: On vulcanisation, sulphur forms cross links at the reactive site of double bonds and thus rubber gets stiffened.
Q.22 Give one use of novolac.
Answer: Used in paints.
Q.23 Give chemical name of orlon.
Answer: Poly acrylonitrile (PAN).
Q.24 Name the polymer used for making handle of pressure cooker.
Q.25 What is the role of benzoyl peroxide in the polymerization of ethene?
Answer: Produces free radical which initiates the chain reaction.
Q.26 Name the polymer of phthalic acid and ethylene ?
Q.27 What are macromolecules?
Answer: Long chain organic molecules which have very high molecular mass are often called macromolecules.
Q.28 Define polymerization.
Answer: The process of formation of a polymer from respective monomers is called polymerization.
Q.29 What are polymers?
Answer: Polymer is defined as very large molecule having high molecular mass formed by repetition of some small monomer units.
Q.30 How are polymers classified on the basis of source?
Answer: On the basis of source polymers are classified as : (i) Natural polymers : Found in plants and animals e.g. Proteins, cellulose, starch, etc. (ii) Semi synthetic: Cellulose derivatives. e.g. Cellulose acetate (rayon) and cellulose nitrate. (iii) Synthetic : e.g. Plastic, nylon-6,6, Buna-S.
Q.31 How are polymers classified on the basis of structure.
Answer: On the basis of structure they are classified as: (i) Linear polymers : e.g. polythene, polyvinyl chloride. (ii) Branched chain : e.g. low density polythene. (iii) Cross linked or network polymers : e.g. Bakelite Melamine.
Q.32 Define copolymer. Give example.
Answer: The polymers made by polymerisation of two different molecules are termed as copolymers. e.g. Buna-S, Buna-N, etc.
Q.33 What are elastomers?
Answer: Elastomers are the polymers in which polymer chains are held by weakest intermolecular force. e.g. Buna-S, Buna-N.
Q.34 Define fibres.
Answer: Fibres are the thread forming solids which possess high tensile strength and high modulus. They are held together by strong intermolecular forces such as H-bond. e.g. nylon 6,6, terylene.
Q.35 What are thermoplastics?
Answer: Thermoplastics are polymers which can be remoulded again and again. e.g. polythene, polystyrene, etc.
Q.36 What are thermosetting polymers?
Answer: Thermosetting polymers are those which cannot be remoulded again. e.g. Bakelite, urea-formaldehyde resins, etc.
Q.37 Give difference between thermoplastic and thermosetting plastics.
|1.||These are linear and slightly branched long chain molecule||These polymers are cross linked and heavily branched molecules.|
|2.||These can be remoulded again and again.||These are not remoulded again.|
Q.38 How is low density polythene prepared?
Answer: Low density polythene is prepared by heating ethene under high pressure of 1000 to 2000 atmosphere at a temperature 350 to 570 K in the presence of traces of dioxide and peroxide initiator.
Q.39 How is high density polythene prepared?
Answer: High density polythene is formed when addition polymerisation of ethene takes place in hydrocarbon solvent in the presence of catalyst such as triethyl aluminium and titanium tetrachloride (also called Ziegler Natta catalyst) at a temperature 333 K to 343 K and under a pressure 6-7 atmosphere.
Q.40 What is vulcanisation of rubber?
Answer: The process of heating a mixture of raw rubber with sulphur at temperature range between 373 K to 415 K in order to make it stiffened is called vulcanization of rubber.
Q.41 What are biodegradable polymers?
Answer: Polymers which do not persist in environment and decompose after some time due to bacterial action are known as biodegradable polymers. e.g. PHBV, nylon-2-nylon-6.
Q.42 What are the bad effects of non-biodegradable polymers?
Answer: Non biodegradable polymers are quite resistant to the environmental degradation processes and cause accumulation of solid polymeric waste materials. These waste materials remain underground for quite a long time and cause acute environmental problems.
Q.43 What are biopolymers?
Answer: Polymers present in plants and animals are called biopolymers. Biomolecules such as carbohydrate, protein, etc. are biopolymers.
Q.44 How does vulcanisation improve the quality of rubber?
Answer: Natural rubber becomes soft at high temperature (> 335 K) and brittle at low temperature (< 283 K). So, in order to make it hard it is vulcanised by adding sulphur. Sulphur forms cross links at the reactive sites of double bonds and thus rubber gets stiffened.
Q.45 How will you differentiate between low density and high density polythene?
|Low density polythene||High density polythene|
|1.||It is prepared under high pressure of 1000-2000 atm.||It is prepared under low pressure of 6-7 atm.|
|2.||It is tough but flexible.||It is tougher and harder.|
|3.||Highly branched structure. So, it has low density due to less closely packed.||It is linearly arranged and has a high density due to close packing.|
Q.46 Give the uses of low density and high density polythene.
Answer: Low density polythene is used in insulation of electricity carrying wires and manufacture of squeeze bottles, toys and flexible pipes. High density polythene is used in manufacture of bucket dustbin bottles, etc.
Q.47 What is synthetic rubber? Give examples.
Answer: Synthetic rubber is any vulcanisable rubber like polymer which is capable of getting stretched to twice its length. e.g. Neoprene, Buna-N, Buna-S, etc.
Q.48 What are polyamide polymers? Give example.
Answer: Those polymers in which amide (-CONH-) linkage is present in the chain are called polyamides. e.g. nylon 6,6, nylon-6.
Q.49 What are polyester polymers? Give example.
Answer: Polyester polymers are the poly condensation products of dicarboxylic acids and diols. e.g. dacron (terylene).
Q.50 Classify the following as thermoplastic and thermosetting polymers. Bakelite, urea-formaldehyde resin, polythene, polystyrene, polyvinyl chloride.
Answer: (i) Bakelite - Thermosetting polymer (ii) Urea formaldehyde resins- Thermosetting polymer. (iii) Polyethene - Thermoplastic polymers (iv) Polystyrene - Thermoplastic polymers. (v) polyvinyl chloride - Thermoplastic polymers.