Exothermic reactions H2SO4 production

H2S04(f) is not made by reacting 803(g) with water. This is because Reaction (1.2) is so exothermic that the product of the 863(g) + H20(f) H2SO4 reaction would be hot H28O4 vapor - which is difficult and expensive to condense. 

During this exothermic reaction at around 120°C and at certain reactant concentrations, an excess of iodine causes a phase separation to occur between the two acid products. That is, the H2SO4 phase is entirely Iree of the HI phase and vice versa. 

However, depending upon the reaction conditions and the nature of the activated carbon surface, several side reactions can occur, which give rise to certain unwanted products such as SO2 and H2SO4. Therefore, the reaction conditions or the active carbons are chosen to eliminate, or at least reduce, the formation of these unwanted products to a negUgible amount. Many times certain types of reaction promoters such as ammonia have been used. The reaction is highly exothermic and, therefore, tends to increase the temperature of the carbon bed. Thus, it is recommended that the catalytic oxidation by active carbon be carried out when the concentration of the H2S in the waste gas does not exceed 3 to 5 gm. ... 

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