A commercial for a well known cleaning powder says that it "shakes out white, then turns blue" what type of reaction os occuring? what compound can one use to produce this effect?

Probably a hydration reaction in which the dry material is one color and the "wet" material is another. I think CoCl2 may do that under the right conditions but the CoCl2 hydrate I've seen is blue when dry and pink when wet.

I just did this lab... I don't know the coumpound, but its Comet the cleaner... and it is a hydration reaction... ^_^

The type of reaction occurring in this case is usually an acid-base reaction. The white powder would consist of an alkaline substance, and when it reacts with an acidic substance, it turns blue.

One common compound that can be used to produce this color change effect is litmus. Litmus is a dye extracted from certain lichens and is available in the form of litmus paper or solution. It is red in an acidic environment and blue in an alkaline environment. Therefore, when an acid-base reaction occurs with a cleaning powder, the litmus will change from red to blue, indicating the change in pH.

The commercial is describing a chemical reaction called a color change reaction. In this specific case, the cleaning powder likely contains a compound that undergoes a color change when exposed to certain conditions.

To produce this effect, manufacturers may use a compound known as a pH indicator, which changes color depending on the pH of the solution it is in. pH indicators are usually made up of weak acids or bases that can be reversible or irreversible. An example of a common pH indicator used in cleaning products is bromothymol blue.

Bromothymol blue is yellow in an acidic solution (pH below 6), but when the cleaning powder is shaken out and mixed with a basic solution (pH above 7), it turns blue. This color change occurs due to the difference in pH between the yellow acidic solution and the blue basic solution.

So, to summarize, the reaction occurring in the commercial is a color change reaction, and a compound like bromothymol blue can be used to produce this effect by acting as a pH indicator.