Precipitation Reaction

[Soaring Crane]

The mixing of which pair of reactants will form in a precipitation reaction?

1) HCl + Ca(OH)2
2) K2SO4 + Ba(NO3)2
3) NaNO3 + NH4
4) CsI + NaOH

It is 2 because BaSO4 is insoluble?

[extraordinarygirl]

Yes, BaSO4 is insoluble which means it is a precipitate