describe and explain the reactions of halide ions with: (a) aqueous silver ions followed by aqueous ammonia (the formation and formula of the \([Ag(NH_3)_2]^+\) complex is not required) (b) concentrated sulfuric acid, to include balanced chemical equations

(a) write and construct equations (which should be balanced), including ionic equations (which should not include spectator ions) (b) use appropriate state symbols in equations

explain, including by use of an equation, the use of chlorine in water purification to include the production of the active species HOCI and CIO\(^-\) which kill bacteria