A precipitate is an insoluble solid product formed from the mixing of two solutions.

Consider the reaction shown on the right. A white insoluble solid (precipitate) is formed when lead nitrate is mixed with sodium carbonate.

Now let's say we mixed two clear solutions of silver nitrate and sodium carbonate. How do we predict the name of the precipitate? Follow the steps listed below and shown in the animation on the right.

Step 1 Write the names of each solution
Step 2 Swap the first names
Step 3 Discard the name that contains any of the following
- sodium
- nitrate
- ammonium
- potassium.

1) Lead nitrate and potassium dichromate

Solution

2) Barium chloride and potassium dichromate

Solution

3) Silver nitrate and potassium dichromate

Solution

4) Lead nitrate and copper sulfate

Solution

5) Lead nitrate and sodium carbonate

Solution

6) Copper sulfate + potassium iodide

Solution

7) Copper sulfate + potassium dichromate

Solution