HCl + HOCl HOCl HCl + Hypo chlorous acid (O) Colouring matter + Nascent oxygen → Colourless oxidation product The bleaching of chlorine is permanent. It oxidises ferrous salts to ferric, sulphites to sulphates and hydrogen sulphide to sulphur. 2FeCl + Cl 2FeCl Cl + H O HCl + HOCl 2FeSO + H S O + HOCl Fe (SO ) + HCl + H O overall reaction 2FeSO + H SO + Cl Fe (SO ) + 2HCl Cl + H O HCl + HOCl Na SO + HOCl Na SO + HCl overal l reaction Na SO + H O + Cl Na SO + 2HCl Cl + H S 2HCl + S Preparation of bleaching powder: Bleaching powder is produced by passing chlorine gas through dry slaked lime (calcium hydroxide). Ca(OH) + Cl CaOCl + H O Displacement redox reactions: Chlorine displaces bromine from bromides and iodine from iodide salts.
Cl + 2KBr 2KCl + Br Cl + 2KI 2KCl + I Formation of addition compounds: Chlorine forms addition products with sulphur dioxide, carbon monoixde and ethylene. It forms substituted products with alkanes/arenes. SO + Cl SO Cl Sulphuryl chloride CO + Cl COCl Carbonyl chloride XII XII - - - - C H + Cl C H Cl ethylene dichloride CH + Cl CH Cl + HCl C H + Cl C H Cl + HCl FeCl → Uses of chlorine: It is used in . Purification of drinking water .
Bleaching of cotton textiles, paper and rayon . Extraction of gold and platinum . . Hydrochloric acid: Laboratory preparation: It is prepared by the action of sodium chloride and concentrated sulphuric acid.
NaCl + H SO NaHSO + HCl NaHSO + NaCl Na SO + HCl Dry hydrochloric acid is obtained by passing the gas through conc. sulphuric acid Properties: Hydrogen chloride is a colourless, pungent smelling gas, easily liquefied to a colourless liquid (boiling point 189K) and frozen into a white crystalline solid (melting point 159K). It is extremely