Final answer:
Ammonium chloride (NH4Cl) when dissolved in water acts as an acid and donate protons to form an acidic solution. The chloride ion (Cl-) produced does not affect the acidity. In a recirculating water system, the impact of NH3 on chlorine depends on the form of chlorine present.
Step-by-step explanation:
Ammonium chloride (NH4Cl) is a salt formed when the strong acid HCl is neutralized by the weak base NH3. When NH3 dissolves in water, it acts as an acid and donates a proton to water, forming hydronium ions (H3O+). This causes the resulting solution to be acidic. The chloride ion (Cl-) produced from the dissolution of NH4Cl does not affect the acidity of the solution because it is the conjugate base of the strong acid HCl.
In a recirculating water system, the impact of NH3 on chlorine depends on the form of chlorine present. Free chlorine species such as Cl2, HOCl, and OCl- are available for disinfecting the water. NH2Cl, NHCl2, and NCl3 are examples of combined chlorine species, where chlorine is in its reduced form and no longer capable of disinfection.