potassium nitrate reacts with copper (I) sulfite, how do you predict the product?

Answer 1

potassium nitrate = KNO3

Copper(I) sulfite = Cu2SO3

Combining the two in solution would proceed by a double displacement/replacement reaction as follows:

2KNO₃(aq) + Cu₂SO₃(aq) ==> K₂SO₃(aq) + 2CuNO₃(aq)