I encountered the fact that $\ce{SO_3}$'s solubility in water is low but even when $\ce{H2S2O7}$ (oleum) is added to water it is $\ce{SO3}$ only that react with water . Please explain the process.


1 Answer 1


The reaction $\ce{SO_3}$ and $\ce{H_2O}$ is exothermic, which means it releases a lot of heat.The heat produced will boil $\ce{H_2SO_4}$ and become $\ce{H_2SO_4}$ gas. The $\ce{H_2SO_4}$ gas is hard to condense causing this method to be unefficient.

  • 3
    $\begingroup$ It would boil water before reaction would end $\endgroup$
    – Mithoron
    Mar 29, 2016 at 19:16

Not the answer you're looking for? Browse other questions tagged or ask your own question.