Aqueous solutions is a kind of solution where in the solvent is water. It is commonly labelled as (aq) after the compound. For example HCl (aq). This also means that the solutes is dissolved in water.
There are kinds of aqueous solutions: ionic and molecular. Ionic aqueous solution is when the solute is an ionic compound or splits into ions when in the solution. Molecular on the other hand do not dissociate into ions in the solution.
In your problem, NaHCO3 or sodium bicarbonate is an ionic compound therefore it forms ions in the solution. Therefore it is called ionic solution.
it's chemical equation is:
NaHCO3 ----> Na+ + HCO3-
Na+ and HCO3- ions are formed when NaHCO3 is dissolved in water.
hope this helps :)