How to Determine If a Substance is an Acid or Base

The pH level of a substance is what determines whether the substance is an acid or base or if it is considered neutral. pH levels are important in many areas of everyday living. Knowing the pH level in a swimming pool will help to prevent chlorine burn and algae growth. pH levels are important in gardening as some plants require higher or lower pH levels than others. Pine trees are one good example of an acid loving plant. Your health can also be affected by your body's pH level and the level in foods you eat.

Numbers in pH levels:

Substances are rated with the numbers 1 through 14. A substance with a pH level of 7 is considered to be neutral. As the pH level number goes down the acid level goes up. A substance with a pH level over 7 is considered to be alkaline and is called a base. Pure water is considered to be neutral with a pH level of 7. Any impurities in water can change the pH level causing it to become more acidic or more alkaline. It is interesting to note that highly alkaline substances can cause burns just as easily as acidic substances.

Litmus testing:

Litmus paper is one of the most common methods used to test a substance's pH level. Paper test strips are chemically coated and will change in color when used for testing pH levels of liquids. Test strips are usually supplied with a color chart to compare your test results with. Paper testing will not necessarily give you 100 percent accurate results but can help you come up with a reasonable determination of a substance's pH.

More expensive and higher quality paper test strips are available for more accurate readings but digital testing will give the most accurate results.

Digital testing:

Digital testing devices are available for ease of use and accurate readings for liquids. Solids can also be dissolved in distilled water to obtain readings. When using this type of testing device it should be calibrated at least as often as recommended by the manufacturer. Buffer solutions are available with a known pH level and the tester you are using should read this pH level when in contact with the buffer. Adjustments can be made to the tester if an incorrect reading of the buffer is obtained. Digital testers can vary widely in price depending on their application and overall accuracy.

Other testing methods:

There are many other testing methods available depending on the substance being tested and the need for accuracy in the test results. For soil testing, tubes are available with a testing solution. A soil sample is placed in the tube and a few drops of the testing solution is added. After a designated period of time the pH level can be read from colors changes.

You can even make your own pH tester by using cabbage. Instructions for this can be found on-line. One site to check for instructions for this is:http://chemistry.about.com/od/chemistryhowtoguide/ht/makephpaper.htm