The answer is c because it is helpful to understand the balance between these two ions. An aqueous solution is a solution in which water is the solvent. Water molecules (H2O) are polar, meaning that they have a negative end (the oxygen) and a positive end (the hydrogens). When there is a reaction in an aqueous solution, the water molecules have the ability to attract and temporarily hold a donated proton (H+). This creates the hydronium ion (H3O+).
