What you’ll learn2 learning objectivesChoose one objective for a focused lesson, or study the complete topic.11.4.1And interpret• Describe and interpret, in terms of changes in oxidation number, the reaction of chlorine with cold and with hot aq. sodium hydroxide and recognise these as disproportionation reactionsSyllabus objective11.4.2Explain• Explain, including by use of an equation, the use of chlorine in water purification to include the production of the active species HOCl and Cl O – which kill bacteriaSyllabus objective