1. Definitions

Bleach extracts and waters" are aqueous solutions of sodium hypochlorite NaClO, generally obtained by reacting chlorine with caustic soda. These solutions also contain the sodium chloride NaCl formed during the reaction: $2\text{NaOH}+{\text{Cl}}_2\to \text{NaClO}+\text{NaCl}+{\text{H}}_2\text{O}$

with ΔH = – 103.2 kJ/mol Cl ₂

In the past, the concentration of bleach waters and extracts was expressed in French-speaking countries in chlorometric degrees, and elsewhere by the quantity of active chlorine. The number of chlorometric degrees was the number of liters...