J. Phys. Chem. 1982, 86. 4857-4863
the competition for the intermediate, but still leaves the formation of the intermediate as the rate-determining step. Because of the low concentrations involved and the lower sensitivity of the Spectronic 20 spectrophotometer used, it was difficult to get accurate concentration measurements for nitrite ion in the low pH stoichiometric experiments where hydrolysis is a major contributor. In addition, the time involved in monitoring the S(1V) concentrations to obtain the stoichiometry limits the number of available data points, which decreases the probability of detecting spurious values. For several conditions measurements were taken to compare to a calculated decay curve for NO2-. Because the third term in eq 1 may be neglected at low bisulfite concentrations and the first term is not observed in the current experiments, only the middle term is needed to calculate the expected nitrite ion decay curve. The rate expression then becomes -d [NO
