Question

What type of reaction produces a precipitate?

Answer 1

See below..

Explanation:

SO SORRY FOR LONG EXPLANATION - but I'm trying to make stuff clear.

Precipitate can be formed when non-soluble substance forms a solid product in a chemical reaction.

How to predict Precipitate?
To determine if a precipitate will form you should know the ions involved and be able to apply the solubility rules.

These are the solubility rules:
1) Group 1 metals on periodic table - all soluble
2) Nitrates (`NO_3^-`) - all soluble
3) Chlorides (`Cl-`) - all soluble EXCEPT `AgCl` and `PbCl_2`.
4) Sulfates (`SO_4^-2`) - all soluble EXCEPT `BaSO_4`,`PbSO_4`, and `CaSO_4`.
5) Hydroxides (`OH^-`) - all NOT soluble EXCEPT `KOH`and `NaOH`.
6) Carbonates (`CO_3^-2`) - all NOT soluble EXCEPT `K_2CO_3`, `Na_2CO_3`, and `(NH_4)_2CO_3`.

Let's say sodium chloride (NaCl) and lead nitrate (`Pb(NO_3)_2`) are given to you to mix them together.

`2NaCl + Pb(NO_3)_2 => 2NaNO_3 + PbCl_2`

`NaNO_3` is soluble (rule 1 and 2)
`PbCl_2` is Not soluble (rule 3)

Since `PbCl_2` is insoluble, therefore it will form a precipitate.

This is what precipitate looks like