The mass-transfer characteristics of a gas-liquid reaction system in a packed column filled with ceramic Raschig rings were studied using the reaction between hydrogen sulfide (H2S) and sulfuric acid solutions. An analysis based on two-film theory shows that the mass-transfer resistance consists of two consecutive steps: gas-side mass transfer and surface reaction. The resistance from the liquid side was negligible because the concentration of sulfuric acid was above stoichiometric and can be regarded as a constant. Onda et al.'s correlations (Onda, K.; Takeuchi, H.; Okumoto, Y. J. Chem. Eng. Jpn. 1968, 1, 56) are able to estimate the effective interfacial area as well as the mass-transfer coefficients for our reactor system. Because the reaction between H2S and concentrated sulfuric acid is a pseudo-first-order reaction with respect to H2S under the experimental conditions used, the approximate equality between the measured overall mass-transfer coefficient and the reaction rate constant suggests the regime of reaction rate control. In other words, the comparison between the rate constants and mass-transfer coefficient is able to show the rate-controlling regimes in terms of operating conditions such as acid concentration, temperature, and acid and gas flow rates. Tests were also carried out with gaseous compounds often found in industrial H2S streams. No reaction was observed for methane, carbon dioxide, carbonyl sulfide, and carbon disulfide. However, the conversion of ethylene was about 20%, and those of mercaptan and thiophene were nearly 100%. This study provides useful data that can facilitate scale-up calculations of this potential sulfur removal and recovery technology.