- In this lab you will observe the color effect that different acid concentrations have on the cabbage testing solution.
MATERIALS NEEDED:
Cabbage indicator (prepared in experiment MAKING CABBAGE INDICATOR)
Scissors
Coffee filter
notebook paper
wax paper
Pencil
Teaspoon
Alum
Cream of tartar
Fruit Fresh (a fruit protector used in canning and freezing)PROCEDURE:
Write alum, cream of tarter, and Fruit Fresh on the notebook paper bout 3 inches apart, then cover with the wax paper.
Place 1/2 teaspoon of each of the 3 powders on the wax paper, below their labels.Be sure to wipe the teaspoon clean between each powder.
Cut three strips, about one-half inch by three inches, from the coffee filter.
Dip the end of one of the filter strips in the cabbage solution. Lay the wet end over the mound of alum.
Wet a second filter strip with cabbage juice and lay over the cream of tartar.The third filter strip is to be wet with the cabbage indicator and placed over the Fruit Fresh.Wait five minutesRESULTS:
- Alum turns the cabbage paper purple, cream of tartar turns the paper pink, and Fruit Fresh produces a rose color.
- The amount of acid present determines the final color change. A strong acid will produce a red color. This test indicates that Fruit Fresh has the most concentration of acid, cream of tartar is next in concentration, and the alum has the least amount of acid. The purple color is produced by the combination of the blue in the test solution and the small amount of red caused by the acid properties of the alum.
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- Alum turns the cabbage paper purple, cream of tartar turns the paper pink, and Fruit Fresh produces a rose color.
COMPARING ACID CONCENTRATIONS
INTRODUCTION: