NaOBr

NaOBr, sodium hypobromite, is the sodium salt of hypobromous acid. It exists mainly as an unstable aqueous solution and, less commonly, as a solid. In solution it acts as an oxidizing agent and a source of HOBr, the active antimicrobial species.

Preparation typically involves reacting bromine with sodium hydroxide: Br2 + 2 NaOH → NaOBr + NaBr + H2O. The reaction is widely used in situ for disinfection, and NaOBr can form during bromination processes in alkaline media.

In aqueous solution, HOBr and OBr- are in equilibrium. The proportion of HOBr, which is more reactive, depends on pH, with HOBr favored at lower pH (pKa about 8.6). Higher pH shifts toward OBr-, reducing disinfection strength.

Stability is limited: NaOBr solutions decompose slowly, especially with heat or organics. Disproportionation can yield bromide and bromate: 3 OBr- → 2 Br- + BrO3-. Solid NaOBr is hygroscopic and should be stored cool and away from reducing agents.

Applications include municipal and industrial water treatment, pool sanitation, and some bleaching processes where bromine-based sanitizers are desired. It is used to generate HOBr in situ for rapid disinfection, but care is required due to its strong oxidizing nature.

Safety: NaOBr is a corrosive oxidizer that irritates skin and eyes. It reacts with acids and reducing agents; store away from heat, acids, and organics, and handle with appropriate PPE.