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What is polymerisation ? Write the example and uses of the reaction. |
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Answer» Solution :(a) definition : Polythene is OBTAINED by the combination of large number of ethene moelcules at HIGH temperature, high pressure and in the presence of a catalyst. The large molecules thus obtained are called polymers. This reaction is known as polymerisation. (b) Example :(i) POLYMERIZATION of ethelene, forms polyethelene. `underset("Ethene")(nCH_(2)=CH_(2))underset("High pressure, catalyst")overset(473-673, O_(2) " High temperature")rarr underset("Polyehene")((-CH_(2)-CH_(2)-)_(n))` (ii) Polymerization of propelene, yields propelene polymer. `underset("Ethene")(nCH_(3)-CH=CH_(2))underset("High pressure, catalyst")overset("High temperature")rarr underset("Polypropene")((-overset(CH_(3))overset(|)(CH_(2))-CH_(2)-)_(n))` (c) Uses : POlymers are USED for the manufacture of plastic bags, squeeze bottles, refrigerator dishes, toys, pipes, radio and T.V. cabinets etc. Polypropeneis used for the manufacture of milk crates, plastic buckets and other moulded articles. Limitations : Though these materials have now become COMMON, excessive use of polyethene and polypropylene is a matter of great concern for all of us. |
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