Abstract: The dependence of the relaxation frequency and the maximum absorption per wavelength of the boric acid relaxation on B(OH)₃ and NaHCO₃ concentrations are obtained by the cylindrical resonator method. The experimental results may be explained by an apparent single-step process:B(OH)₃+CO₃^2- (total) + H₂O⇌B(OH)₄^- (total)+ HCO₃^2- (total). Theory and experimental results show that the. effects of calcium on the relaxation parameters of the boric acid relaxation can be interpreted by a coupled reaction system, which is equivalent to that apparent single-step process, including all ion association reactions.