Suppose that you wanted to form baco3 as a precipitate in an aqueous reaction. what aqueous solutions would you choose as reactants? 1. not possible since baco3 is soluble 2. bacl2 and caco3 3. baso4 and na2co3 4. ba(no3)2 and k2co3

The answer is Ba(NO3)2 and K2CO3.
The explanation in each choice will be explained:
1. is not true because BaCO3 is insoluble in water. 
2. CaCO3 is insoluble but not much CO3^2- in solution.
3. BaSO4 is insoluble, not much Ba2+ in solution.
4. Ba(NO3)2 and K2CO3 are both soluble in water.