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प्रश्न
Low density polythene and high density polythene, both are polymers of ethene but there is marked difference in their properties. Explain.
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उत्तर
| LDP | HDP |
| 1. It is obtained by the polymerisation of ethene under high pressure of 1000 to 2000 atmospheres at a temperature of 350 K to 570 K in the presence of traces of dioxygen or a peroxide initiator (catalyst). | 1. It is formed when addition polymerisation of ethene takes place in a hydrocarbon solvent in the presence of a catalyst such as triethylaluminium and titanium tetrachloride (Ziegler-Natta catalyst) at a temperature of 333 K to 343 K and under a pressure of 6-7 atmospheres. |
| 2. (LDP) is obtained through the free radical addition and H-atom abstraction. It has highly branched structure. | 2. (HDP) thus produced, consists of linear molecules as shown below and has a high density due to close packing. |
| 3. Low-density polythene is chemically inert and tough but flexible and a poor conductor of electricity. | 3. It is also chemically inert and more tough and hard. |
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संबंधित प्रश्न
Write the molecular formula and structural formula of BHA and BHT.
What is the role of t-butyl peroxide in the polymerization of ethene?
Write the mechanism of free radical polymerization of ethene.
Write the free radical mechanism for the polymerisation of ethene.
Write chemical reaction to prepare the Dextron polymer:
Dextron
Which of the following statements is not true about low-density polythene?
Why should the monomers used in addition polymerisation through free radical pathway be very pure?
Match the polymers given in Column I with their chemical names given in Column II.
| Column I | Column II |
| (i) Nylon 6 | (a) Polyvinyl chloride |
| (ii) PVC | (b) Polyacrylonitrile |
| (iii) Acrilan | (c) Polycaprolactum |
| (iv) Natural rubber | (d) Low-density polythene |
| (v) LDP | (e) cis-polyisoprene |
Assertion: Polytetrafluoroethene is used in making non-stick cookwares.
Reason: Fluorine has highest electronegativity.
By which reaction ethene is obtained from ethyne?
Which one of the following can be used as monomer in a polymerisation reaction?
The Ziegler Natta catalyst are
Which of the following is chain-growth polymer?
Which one of the following polymers are prepared by addition polymerisation?
Which one of the following polymers is prepared by addition polymerisation?
\[\ce{X + C + Cl2 ->[High temperature][of about 1000 K] Y + CO}\];
\[\ce{Y + 2H2O -> Z + 2HCl}\]
Compound Y is found in polymeric chain structure and is an electron-deficient Molecule. Y must be:
