Natural Acid/Base Indicator Lab
Using Beet Juice to Unveil Acids and Bases Around the House
Purpose
The purpose of the natural indicator lab was to indicate which household substances were acidic, basic, or neutral. This was accomplished by referencing the given substances with pH values of 1, 3, 5, 7, 9, 11 and 13. We were then able to compare our household substances to the given substances and draw conclusions about their pH, with the use of beets as our indicator. Indicators are what enable us to see different values on the pH scale, by seeing a wide range of color. Red is the most acidic end of the scale (1-6) and dark blue is the most basic (8-14). A pH value of 7 is neutral and appears as green. Acids are hydrogen-containing compounds that ionize to yield hydrogen ions in aqueous solutions. Bases are compounds that ionize to yield hydroxide ions in aqueous solutions. The four household substances that we tested were vegetable oil, lysol, clear nail polish and nail polish remover.
Introduction
- We used clear vegetable oil, clear nail polish, clear nail polish remover, and clear lysol cleaning spray.
- An acid is a substance with a pH level of 1-6. A base is a substance with a pH level of 8-14.
- An indicator indicates whether a substance is acidic, basic, or neutral. The color changes indicate the pH level of the substance. For example, Bromothymol Blue indicator changes from blue to yellow with a substance of pH level 6.0.
Procedure
Solid Form of Indicator
These are the beets before processing.
Liquid Form of Indicator
This is the beet juice.
Household Substances Used
Our four household substances... (listed from left to right): Vegetable Oil, Lysol, Clear Nail Polish, Nail Polish Remover
Determining pH of Household Substances
This picture was taken after the indicator (beet juice) and the household substances were mixed together. We used the known substances (with known pH values) to compare the color of the household objects after being mixed with the indicator. The pinker the substance became, the more acidic it was. The darker and more purple the substance was, the more basic it was.
Conclusions
- The colors for acids with pH values 1, 3, and 5 with the beet indicator was a deep magenta color.
- The colors of bases with pH values 9, 11 and 13 with the beet indicator was a deep purple color.
- Our indicator (beet juice) was better at deciding bases because for the bases it changed to a color that was more different than the original color of the beet juice which is a dark magenta color, and that was also similar to the colors of the acids. However, with the bases you saw a more drastic change from pink to deep dark purple.
- A problem with our natural indicator when figuring out the pH values was that all of the colors for the acids looked identical, and had no variation of color.
- I think we would choose different, stronger substances to try and see a greater change in color, especially for the acids with the beet indicator.
Sources
**We used notes from class as a reference
**Picture used at very beginning of raw beets came from the following source: