Some chemicals are acids and some are bases. We can test these chemicals with different indicators and determine if they are an acid or a base. Cabbage juice is an example of an acid-base indicator. If a solution of lemon juice is poured into purple cabbage juice, it will turn red. This indicates that it is an acid. If drain cleaner is added to cabbage juice, it will turn green indicating that it is a base. Other materials can also be used as indicators if they change color in the presence of an acid or base. Litmus paper and phenolphthalein are commonly used in a chemistry lab but many other plant materials such as beets, blackberries and blueberries will also work.

A student was given an unknown liquid. She tested it and recorded the following observations

Based on the information above, what was the most likely pH of the resulting solution?

3

5

7

12