the answer: the equation is  H2CO3 + H2O ---> HCO3- + H3O+, it is a reaction equation of an acid in an aqueous solution. in this equation, the water behaves as solvent. (aqueuse solution) the acid H2CO3 is a weak acid, so the definition which would be applied is  the definition of the dissociation of a weak acid from the aqueous solution. the reaction equation given above shows that.