Question

What is the formula of the precipitate formed from the precipitation reaction of Pb(NO3)2 and NaI?


QUESTION 2

When aqueous solutions of (NH4)3PO4 and KOH are mixed, what precipitate(s) will form?

K3PO4

NH4OH

no precipitate will form

NH4OH and K3PO4

Answer 1

You need to know the solubility rules. Here is a set.
https://chem.libretexts.org/Core/Physical_and_Theoretical_Chemistry/Equilibria/Solubilty/Solubility_Rules