Final answer:
The purpose of the experiment to determine pH using red cabbage extract is to use the natural pH indicators present in red cabbage to determine the pH of different solutions.
Step-by-step explanation:
The experiment with red cabbage extract helps figure out how acidic or basic (alkaline) different liquids are. Red cabbage contains a mixture of colored substances that change color depending on the pH of the solution. By extracting the red cabbage juice and adding it to different solutions, the color change can be observed and used to determine the pH of the solution. This is a simple and inexpensive way to measure the acidity or alkalinity of a substance.