pH Paper Use and Application

1. pH is a chemical property of matter that allows us to classify a substance as an acid, a base, or neutral. It is measured on a scale from 0 to 14 known as the pH scale. On this scale, the number 7 represents a neutral substance. All numbers less than 7 represent an acidic substance, and all numbers greater than 7 represent a basic substance.

2. pH can be measured using a variety of tools. Two tools used in the science lab are pH paper and pH indicator strips.

3. If using pH paper, tear a piece of paper from the pH paper dispenser. The piece of pH paper should be approximately 7 or 8 cm in length.

4. If using pH indicator strips, remove one strip from the box.

5. Using either pH paper or an indicator strip, dip the paper or strip into the liquid substance to be tested. Dip the paper or strip so that 2 to 3 cm are in the liquid. The color boxes on the indicator strip should be placed completely in the liquid.

6. Remove the strip of paper from the substance. Immediately compare the color of the paper or strip to the color key on the container.

7. The color key allows you to determine the pH of the liquid substance. Find the color on the key that best matches the color of the paper or strip. If using a pH indicator strip, make sure that all four colored boxes match with all four colored boxes on the color key.

8. After finding the pH, use the pH scale to determine whether the substance is an acid, a base, or a neutral substance.