Question

Name the oxide of sulphur that react with water to give sulphuric acid.

Answer 1

1. The oxide is Sulphur trioxide$\left({\mathrm{SO}}_3\right)$
2. It is one of the easy ways to produce ${\mathrm{H}}_2{\mathrm{SO}}_4$
3. But adding ${\mathrm{SO}}_3$to water is a highly exothermic process, also it generates a cloud of fumes which further restricts the addition of more water to ${\mathrm{SO}}_3$.
4. So, this process is avoided to prepare sulphuric acid.
5. $$\begin{gathered} {\mathrm{SO}}_3\left(\mathrm{g}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to {\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{l}\right) \\ \mathrm{Sulphur}\mathrm{trioxide}+\mathrm{water}\to \mathrm{Sulphuric}\mathrm{acid} \end{gathered}$$