How to write net ionic equations?

Question

I have few ionic equations I don't understand. Can you help me with some explanation?

1.Lead nitrate + potassium iodide
2.Hydrochloric acid + sodium hydroxide
3. zinc metal + hydrochloric acid
4. Copper wire + silver nitrate


Thanks..

Answer 1

The easiest way is to write the equation with the products. Then look at a table of solubilities to determine which of the products forms a precipitate. The ions which form the precipitate, gas, or liquid are the net ionic equation.

Pb(NO3)2 (aq) + 2 KI (aq) --> PbI2 (s) + 2 KNO3 (aq)
All nitrates are soluble, Pb2+ forms an insoluble ppt with halide ions.
Pb 2+(aq) + 2 I 1-(aq) --> PbI2 (s)
the other ions do not enter into the reaction so they are spectator ions.

HCl (aq) + NaOH (aq) --> NaCl (aq) + H2O (l)
Since the Na and Cl are both aq in the reactants and products, they are the spectator ions. Leave them out and write the net ionic equation:
H 1+ (aq) + OH 1- (aq) --> H2O (l)

Zn (s) + 20HCl (aq) --> ZnCl2 (aq) + H2 (g)
The only thing that remains aq is the Cl. Leave this out and write your net ionic as:
Zn (s) + 2 H 1+ (aq) --> Zn 2+ (aq) + H2 (g)

Cu (s) + 2 AgNO3 (aq) --> Cu(NO3)2 (aq) + 2 Ag (s)
The only ion that remains aq is the NO3. Leave it out and write:
Cu (s) + 2 Ag 1+ (aq) --> Cu 2+ (aq) + 2 Ag (s)