Which chemical reaction equation represents the dissociation of hypochlorite acid?

• A. HCl + NaOH -> NaCl + H2O
• B. Cl2 + H2O -> H+ + Cl- + HOCl
• C. HOCl -> H+ + OCl-
• D. ClO- + H2O -> Cl- + H2O2

Answer: (B)

Dissociation of an acid means the molecule splits in water to form ions, releasing a proton and leaving behind its conjugate base. For hypochlorous acid, this means HOCl breaks apart to give a proton and the hypochlorite ion: HOCl ⇌ H+ + OCl−. This captures the idea of a weak acid releasing H+ to form its conjugate base.

This representation is the best because it directly shows HOCl becoming H+ and OCl−, which is the defining feature of dissociation. The other reactions involve different processes: HCl reacting with NaOH is a neutralization, Cl2 reacting with water is a hydrolysis/disproportionation step, and ClO− transforming with water to form Cl− and H2O2 is a redox-type transformation. None of those describe HOCl simply dissociating into ions in solution.

Contextually, HOCl is a weak acid whose dissociation is pH-dependent, with more HOCl present at lower pH and more OCl− at higher pH, affecting disinfection efficacy.