Identify which indicator will you use to identify a substance as an acid or a base.

To identify a substance as an acid or a base, you can use a pH indicator. A pH indicator is a halochromic chemical compound that is added in small amounts to a solution so that the pH (acidity or basicity) of the solution can be determined visually.

Here are the steps:

1. Obtain the substance you want to test.

2. Add a small amount of the pH indicator to the substance.

3. Observe the color change.

4. Compare the color of the substance with a pH scale.

If the color matches the colors representing 0-6 on the pH scale, the substance is an acid. If the color matches the colors representing 8-14 on the pH scale, the substance is a base. If the color matches the color representing 7 on the pH scale, the substance is neutral (neither acidic nor basic).

Common pH indicators include litmus paper, phenolphthalein, and bromothymol blue. Litmus paper turns red in acidic conditions and blue in basic conditions. Phenolphthalein turns fuchsia in basic conditions and is colorless in acidic conditions. Bromothymol blue turns yellow in acidic conditions and blue in basic conditions.