Hypochlorous acid (HOCl) can be made pure in the gas phase, Equation 1, while strong acid solutions can be made from Cl_{2}O. In contrast, dilute aqueous solutions are obtained with a suspension of mercury oxide to remove the chloride, Equation 2.

Solutions of the anion, OCl^{-}, are obtained by electrolysis of brine solution; allowing the products to mix at low temperature, Equation 3.

The anion (hypochlorite) is a good oxidant, Equation 4 and Equation 5, but can undergo disproportionation, Equation 6; slowly at 25 °C, but fast above 80 °C.