Question

Dissolution of $S{O}_3$ in water is ________.

Answer 1

Sulfur trioxide (${SO}_3$) dissolves in and reacts with water to form an aqueous solution of sulfuric acid ($H_2{SO}_4$). The vapor in equilibrium with the solution contains both ${SO}_3$ and $H_{2}O$. If enough ${SO}_3$ is added, all of the water reacts and the solution becomes pure $H_2{SO}_4$.

This dissolution of ${SO}_3$ in water is exothermic.

${SO}_3+H_{2}O⟶H_2{SO}_4$