Converting Aluminum to Aluminum Potassium Sulfate

Review Questions

Not for Credit


Step 2: Dissolve the Aluminum

Place the pieces of aluminum foil in a 250 mL beaker.

Measure out 5 mL of 1.4 M KOH in a graduated cylinder.

Then pour the KOH solution into the beaker containing the small pieces of foil.

Place the beaker with the KOH and small pieces of foil on a hot plate underneath the individual fume hood at your lab bench. It should take about 5 - 10 minutes for the aluminum to dissolve with the hot plate set at medium heat.

Stir occasionally with a glass stirring rod.

The solution should turn a dark charcoal gray color.

If the liquid drops to ¼ the initial volume while heating, add some distilled water carefully to bring the level of the liquid back up to ½ of the original volume. Stir occasionally with a glass stirring rod.

After 5- 10 minutes on the hot plate, the glass beaker will be hot.

Do not attempt to remove the beaker with your bare hands or you will get burned.

Use a pair of beaker tongs or an oven mitt to remove the beaker from the hot plate once the aluminum has dissolved.

Set the beaker aside to cool on your laboratory bench.

Measure 6 mL of 6 M sulfuric acid (H2SO4) in a clean graduated cylinder.

When your beaker is cool to the touch (this may take a few minutes), slowly add the 6 mL of the sulfuric acid while stirring with a glass stirring rod.

This should be done under the hood.


A pulpy white substance will form; with stirring, however, it should dissipate. This white solid is the precipitate of Al(OH)3 (s) discussed in the introduction.

Continue to stir until your solution is translucent.