# What is the common name for Na_2SO_3?

$N {a}_{2} S {O}_{3}$ is $\text{sodium sulfite}$
We have $S \left(I {V}^{+}\right)$ rather than the $S \left(V {I}^{+}\right)$ observed for $\text{sulfuric acid}$, ${H}_{2} S {O}_{4}$. ${H}_{2} S {O}_{3}$ is $\text{sulfurous acid}$, or the hydrate of $\text{sulfur dioxide}$, i.e. ${O}_{2} S \cdot O {H}_{2}$. I think that solutions of this salt have a pleasant, pharmaceutical smell.