H2CO3 is commonly known as Carbonic acid. As the name suggests, this compound is an acid. Generally an acid, is a proton donor, has a pH below 7, neutralizes base and turns blue litmus paper to red. This also means that in a solution (in water) H2CO3 produces Hydronium ions (H3O+ ions).

The chemical equation for the dissociation of Carbonic acid (H2CO3) in the solution can be written as:

H2CO3 (aq) + H2O <--->  H3O+  + CO3-

 **hydronium ions can be represented as H3O+ or simply H+. 

Carbonic acid is classified as a weak acid