(a)(i) Define polymerization. (ii) Mention two types of polymerization. (iii) Give one example of I. naturally occurring polymer, II. synthetic polymer. (b)(i) Describe how ethyne could be prepared in the laboratory. (ii) Write an equation for the I. polymerization of ethyne II. complete reaction of ethyne with hydrogen bromide. (iii) Name each of the products formed in (b)(ii) II. (c)(i) Define each of the following terms: I. pollution; Il. pollutant. (ii) Mention three types of pollution. (iii) Give two ways by which pollution can be prevented.
Explanation
(a) (i) Polymerization is a process whereby many small molecules (monomers) link together to form a giant molecule (polymer) (ii) - addition polymerization -condensation polymerization. (iii) I. starch/cellulose/ proteins/natural rubber/latex. II. polythene(polythene)/PVC/polystyrene/nylon/perplex.
(b) (i) Ethyne is prepared in the laboratory by the action of water on cc!cium dicarbide. The gas evolved is passed through a solution of copper II tetraoxosulphate (VI) to remove impurities and the ethyne is collected over water by upward delivery. (ii) I. 3C\(_2\)H\(_{2(g)}\) \(\to\) C\(_6\)H\(_{6(g)}\) II. C\(_2\)H\(_2\) + 2HBr \(\to\) C\(_2\)H\(_4\)Br\(_2\)/ H - C\(\equiv\)C – H + 2HBr \(\to\) CH\(_3\)CHBr\(_2\).
(iii) I. Benzene II. 1,1 – dibromoethane
(c) I. Pollution is the presence of harmful substances in the environment in concentrations that cause injury to life and property. (II) Poil spillage prevention - enlightenment programme - tree planting -proper sewage disposal. (ii) - Air pollutions - water pollutgion - land/soil pollution (iii) - Use of anti-pollutants in automobiles - promulgation of laws with effective monitoring - oil spoilage prevention - elightenment programme - tree planting - proper sewage disposal
