Open book coursework the extraction of chlorine and iodine
The Extraction Of Chlorine and Iodine Chlorine and Iodine are both group 7 elements, which need extracting from their sources before they can be used. ... Electrolysis is needed to extract chlorine - in a modern membrane cell where electrolysis of chlorine takes place the reaction at the anode (positive electrode) is this: 2cl- - 2e Cl2(g) This is an oxidation reaction because the chloride ions are loosing electrons to produce chlorine atoms. The chlorine becomes liberated at the anode. ... To produce iodine in the 19th century seaweed was burnt and then the ash boiled with water in metal tanks. Sludge was left at the bottom of the tank after the process, sulphuric acid was added to remove this sludge, this acid was a powerful enough oxidising agent to convert the iodine ions into iodine molecules. ... Chlorine gas will react with hydrogen to form hydrogen chloride which is not required. ... In the mercury cathode the chlorine and hydrogen are kept apart because the chlorine is produced in a different container from the hydrogen and sodium hydroxide meaning they do not come into contact with each other.