# Is CO2 an acid or a base?

Acids have the general formula ${H}_{x} A$ which means that they have to possess one hydrogen atom at least, which is not the case of carbon dioxide $C {O}_{2}$.
However, $C {O}_{2}$ when it dissolved in water it forms the carbonic acid:
$C {O}_{2} \left(g\right) + {H}_{2} O \left(l\right) r i g h t \le f t h a r p \infty n s {H}_{2} C {O}_{3} \left(a q\right)$