Testing pH Lab
Background
A liquid may be an acid, base, or neutral. The degree of acidity or basicity can be
measured by using the pH scale. The scale is divided into three areas: Acid
(readings below 7), neutral (reading of 7), and basic (readings above 7). Each
division either increases or decreases the pH of a substance 10 times. For
example, the pH of 5 is ten times more acidic than a pH of 6. Water has a pH of 7
but when it mixes with air the suspended materials will either raise or lower its
pH. Acid Rain is an example of this type of reaction. Universal indicator paper
changes depending on the pH of the solution being tested. Many substances
around your home are acids with a low pH. Others are bases and have a high
pH.
Purpose
To determine the pH of some common solutions
Materials
- 50 ml beaker (#)
- Various common solutions
- Red litmus paper
- tweezers
- pH indicator paper and chart
- Blue litmus paper
Procedure
1) Obtain a test tube rack containing several test tubes of various common
solutions.
2) Before testing each known solution, hypothesize about the pH of each of the
known solutions. Use your previous knowledge of the solutions and knowledge of
pH to create your hypothesis. Record your hypothesis in Table 1.