Introduction
In the course of the experiment, red cabbage extract was dissolved in water to test the pH level of household chemicals. According to Abedi-Firoozjah (2022), “red cabbage extract (RCE) is a common and rich source of anthocyanins, which are closely related to the pH of their environment” (p. 3). Indeed, red cabbage water solution allows for identifying the level of pH in any liquid solution in one’s household, with the color change demonstrating the acidity level. The pH level of red cabbage extract ranges “from red color at pH 1–2, pink at pH 3, violet at pH 4–6, blue at pH 7–8, green at pH 9–11, and yellow at pH 12” (p. 3). During the experiment, most of the results were predictable, while the pH level of bleach was surprising due to its non-acidic nature.
Discussion
When adding vinegar to RCE, the color changed into bright pink, which indicates pH 3; similarly, when mixed with lemon soda, the solution was purple-pink, which is about pH 4. When mixed with plain water, the solution did not change color, which implies that pH 7 remained unchanged. The toothpaste dissolved in water was mixed with RCE, which changed color into light blue, which indicates pH 8; the baking soda solution mixed with RCE was colored blueish green, demonstrating pH 9. The solution mixed with a window cleaning product became yellow-green, which is a base with pH 10-11. Bleach mixed with RCE was light yellow, which indicates pH 12. Table 1 demonstrates the results of the experiment in detail.
Table 1: Experiment results
Conclusion
Overall, while most results were correctly predicted, the base level of bleach was the most surprising. The lowest level of pH was found in vinegar, which is the strongest acid of all tested products. The highest level of pH was found in bleach, which is a base. When explaining the term strong acid to someone unfamiliar with chemistry, one might state that it is a substance that dissociates in water and has a low pH level. Conclusively, this experimentation has demonstrated how RCE might be effectively used as a pH indicator.
Reference
Abedi-Firoozjah, R., Yousefi, S., Heydari, M., Seyedfatehi, F., Jafarzadeh, S., Mohammadi, R., Rouhi, M., & Garavand, F. (2022). Application of red cabbage anthocyanins as pH-sensitive pigments in smart food packaging and sensors. Polymers, 14(8), 1-21.