Our earlier study showed that when H2S and concentrated sulfuric acid react, H2S is first oxidized by molecular H2SO4 and then consecutively by SO2, a product of the first oxidation step. The rate of the first reaction was measured using initial rate analysis at temperatures and acid concentrations under which conditions the second reaction may be neglected. In this study, the kinetics of the second reaction, 1 e, the reaction between hydrogen sulfide and sulfur dioxide in sulfuric acid solutions, was studied at 20-50 degreesC and 30-60 wt % of acid concentration, under which conditions the rate of the first reaction is negligible. The second reaction follows first-order kinetics with respect to the partial pressure of H2S in the gas phase and also to the concentration of SO2 in the solution. Changes in acid concentration do not affect the rate constant. The activation energy and the preexponential factor of the reaction at all acid concentrations studied are 59 02 kJ mol(-1) and 11 900 L s(-1) M-2 Pa-1, respectively. Further experiments show that the measured kinetic results also apply to the second reaction in sulfuric acid at concentrations exceeding 60 wt %.