Research Product

Hypochlorus acid is the first product formed when chlorine gas is added to water. Both its toxicity to aquatic organisms and the rate at which it forms subsequent reaction products are influenced by the degree to which it ionizes in the receiving water. Based on potentiometric titrations with a glass electrode, the apparent ionization constant in artificial seawater is described by the following equation: pK'c = 937.7 T (to the negative power 1) - 0.149 Cl1/3 + 4.433, where T is absolute temperature and Cl is chlorinity in g/kg. Under the pH and temperature conditions prevailing in typical estuaries, the less toxic, nonprotonated form predominates. There is evidence that this form participates in iron-pair formation to a small degree in seawater. The equilibrium concentration of the protonated form HOCl, is enhanced by low pH, low temperature, and low salinity.