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State properties and uses of dichlorine. |
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Answer» Solution :(i) Physical properties : It is a greenish-yellow gas with pungent and suffocating odour. It is about 2-5 times heavier than air. It is soluble in water and can be liquefied easily into yellow liquid which boils at 239K TEMPERATURE. (ii) Chemical properties : Reaction with metals and non-metals : Chlorine reacts with all non-metals EXCEPT NITROGEN, oxygen, carbon and inert gases. Chlorine with metals and non-metals form chlorides. `2Al + 3Cl_2 to2AlCl_3 , P4 + 6Cl_2 to4PCl_3 2Na + Cl_2 to 2NaCl , S_8 + 4Cl_2to 4S_(2)Cl_(2)` `2Fe + 3Cl_(2) to 2FeCl_(3)`, Affinity for hydrogen : Chlorine has very strong affinity for hydrogen. It reacts with compounds containing hydrogen to form HCl `2 + Cl_2 to2HCl` `H_2S + Cl_2 toS + 2HCl` `C_10H_16 + 8Cl_2 to 16HCl + 10C` Reaction with alkalies : With cold and dilute alkalies chlorine produces a mixture of chloride and hypochlorite but with hot and concentrated alkalies it GIVES chloride and chlorate. `2NaOH + Cl_(2) to NaCl + NaOCl + H_(2)O` `6NaOh + 3Cl_(2) to 5NaCl + NaClO_(3) + 3H_(2)O` Reaction with ammonia : With ammonia, the products obtained are ammonium chloride and dinitrogen. `3Cl_(2) (g) + 8NH_(3)(g) to N_(2)(g) + 6NH_(4)Cl(s)` With excess dichlorine the product is `NCl_3` (explosive) `NH_(3)(g) + 3Cl_(2)(g) to NCl_(3) + 3HCl(g)` Bleaching action and oxidizing action: Chlorine water on standing loses its yellow COLOUR due to the formation of HCl and HOCl. Hypochlorous acid so formed, gives nascent oxygen which is responsible for oxidising and bleaching properties of chlorine. `Cl_2 + H_2O toHOCl + HCl` `HOCl to HCl + [O]` `2FeSO_4 + H_2SO_4 + Cl_2 to Fe_2(SO_4)_3 + 2HCl` `Na_2SO_3 + Cl_2 + H_2O toNa_2SO_4 + 2HCl SO_2 + 2H_2O + Cl_2 toH_2SO_4 + 2HCl` `I_2 + 6H_2O + 5Cl_2 to2HlO_(3) + 10HCl` The bleaching action of chlorine is permanent as it takes place through oxidation. It bleaches vegetable and organic matter in presence of moisture. Coloured matter + [O] `to` colourless substance Formation of bleaching powder : With dry slaked lime, it gives bleaching powder. `2Ca(OH)_(2) + 2Cl_(2) to Ca(OCl)_(2) + CaCl_(2) + 2H_(2)O` The composition of bleaching powder is `Ca(OCl)_(2).CaCl_(2).Ca(OH)_(2).2H_(2)O` Reaction with hydrocarbons : With saturated hydrocarbons, dichlorine gives substituted products and with unsaturated hydrocarbons it gives addition products. `CH_(4) + Cl_(2) overset(hv)to underset("Methyl chloride")(CH_(3)Cl + HCl)` `C_(2)H_(4) + Cl_(2) overset("Room")underset("Temperature")to underset(1,2 "dichloroethane")underset(Cl)overset(CH_(2))| - underset(Cl)overset(CH_(2))|` Uses of dichlorine : For bleaching wood pulp (required for the manufacture of paper and rayon), cotton and textiles. In extraction of gold and platinum. In the manufacture of dyes, drugs and organic compounds such as `C Cl_4, CHCl_3`, DDT, refrigerants etc. In sterilising drinking water and in preparation of poisonous gases such as phosgene (`COCl_2`), tear gas (`C Cl_3NO_2`), mustard gas: `[Cl-CH_(2)CH_(2)-S-CH_(2)CH_(2)-Cl]` |
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