Hypochlorous acid Hypohalites

Since hypohalous acid is a much more active disinfectant than the hypohalite ion, the effect of pH on ionization becomes important. Hypobromous acid has a lower ionization value than hypochlorous acid and this contributes to the higher disinfectant activity of BrCl compared with chlorine. 

The addition of silver or mercury oxide precipitates the metal halide, leaving behind the aqueous solution, which is very reactive and is used for bleaching and sterilizing purposes. Solutions of hypohalites can be made by introducing the appropriate halogen into basic solutions (equation 113), but these will also contain some halide anions. To obtain pure hypochlorites, it is necessary to carefully neutralize pure hypochlorous acid. The most stable hypochlorites are those of Li, Ca, Sr, and Ba, although some others are also known but are not as stable, or are not sufficiently pure. 

The hypohalites are used as bleaching agents. Sometimes CI2 is used as a bleach or as a disinfectant, as in public water supplies. It reacts slowly with H2O to form HCl and HOCl. The hypochlorous acid then decomposes into HCl and O radicals, which kill bacteria. 

Hypochlorous acid (s. a. Hypo-halites) 16,231 19,197 Hypohalites (s. a. Alkyl hypo-halites, Potassium hypo-bromite, — hypochlorite, Sodium hypochlorite, — hypoiodite) 17, 352 Hypophosphite s. Sodium dihydrogen hypophosphite Hypophosphoric acid esters... 

---