This is kinda a trick question. The rxn you wrote above will not occur. Barium Carbonate is insoluble and therefore will not dissociate in water. HCl will fully dissociate, but if it has no other ions to react with, then there will be no rxn and thus no net ionic equation.
Precipitation reactions are sometimes called "double displacement" reactions. To determine whether a precipitate will form when aqueous solutions of two compounds are mixed:
1. Write down all ions in solution.
2. Combine them (cation and anion) to obtain all potential precipitates.
3. Use the solubility rules to determine which (if any) combination(s) are insoluble and will precipitate.
Examples:
a. What happens when Ba(NO3)2(aq) and Na2CO3(aq) are mixed?
Ions present in solution: Ba2+, NO3-, Na+, CO32-
Potential precipitates: BaCO3, NaNO3
Solubility rules (Reference Kaplan Book) : BaCO3 is insoluble, NaNO3 is soluble
Complete chemical equation: Ba(NO3)2(aq) + Na2CO3(aq) --> BaCO3(s) + 2 NaNO3(aq)
Net ionic equation : Ba2+(aq) + CO32-(aq) --> BaCO3(s)
When writing net ionic equations how do you know what ions will dissassociate and which ones won't?
If you aren't familiar with the solubity rules of various salts here they are if you want to refresh your memory:
1 All compounds containing alkali metal cations and the ammonium ion are soluble.
2 All compounds containing NO3-, ClO4-, ClO3-, and C2H3O2- anions are soluble.
3 All chlorides, bromides, and iodides are soluble except those containing Ag+, Pb2+, or Hg22+.
4 All sulfates are soluble except those containing Hg22+, Pb2+, Sr2+, Ca2+, or Ba2+.
5 All hydroxides are insoluble except compounds of the alkali metals, Ca2+, Sr2+, and Ba2+.
6 All compounds containing PO43-, S2-, CO32-, and SO32- ions are insoluble except those that also contain alkali metals or NH4+.
