When potassium iodide (KI) is mixed with barium nitrate (Ba(NO3)2), a chemical reaction takes place, resulting in the formation of two new compounds: barium iodide (BaI2) and potassium nitrate (KNO3). The reaction can be represented by the following equation:

2KI + Ba(NO3)2 → BaI2 + 2KNO3

In this reaction, the potassium ions (K+) from KI combine with the nitrate ions (NO3-) from barium nitrate to form potassium nitrate (KNO3). Simultaneously, the barium ions (Ba2+) from barium nitrate combine with the iodide ions (I-) from KI to form barium iodide (BaI2).

The products of this reaction, barium iodide (BaI2) and potassium nitrate (KNO3), are both soluble in water. Barium iodide is a white crystalline solid, while potassium nitrate is a colorless or white crystalline solid.