Complete and balance the chemical equation using compound formulas. Include the states. If there is no reaction, enter NR.

Question

Pb(NO3)2(aq) + NaI(aq) →
sine Pb is not reactive, the reaction is NR. Am i correct?

Answer 1

No. Pb^+2 forms PbI2 with the I^- from NaI. PbI2 is insoluble and that is what drives the reaction.
Pb(NO3)2(aq) + 2NaI(aq) ==> PbI2(s) + 2NaNO3(aq)
In reactions of this type, there are three reasons for a reaction occurring.
1. A ppt is formed. For this you need to know the solubility table. Here is a simple one on the web.
http://www.files.chem.vt.edu/RVGS/ACT/notes/solubility_rules.html
2. A gas is formed. You know the simple ones; i.e., H2, O2, F2, Cl2, CO, CO2, N2, etc.
3. A slightly ionized material is formed; i.e., a weak electrolyte.
4. There are different rules for redox equations.