How to Determine if a Water Solution Is Acid or Base
Two hydrogen (H) atoms and one oxygen (O) atom make up a single water molecule (H20). Sometimes water molecules in solution break up to form hydrogen ions (H+) and hydroxide ions (OH-). When the number of hydrogen and hydroxide ions in a solution is equal, scientists say the solution is neutral. When there are more H+ ions than OH- ions, the solution is acidic. When there are more OH- ions than H+ ions, the solution is basic, or alkaline. pH strips are a way of determining if a water solution is acidic or basic.
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Instructions
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Buy a package of pH strips at any drugstore, laboratory supply store or online (see Resources).
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Place a piece of blotting paper or absorbent paper towel on a table in front of you.
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Place a single pH strip on the piece of blotting paper or paper towel.
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Place a drop of the water solution you want to analyze on the pH strip using an eyedropper or follow the manufacturer's instructions. Do not place the pH strip in the solution itself to avoid contaminating the solution.
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Note the color change of the pH strip and compare it to the manufacturer's color-range chart that comes with the pH strip.
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Determine the pH of your solution by reading the pH on the chart, identifying the color on that chart closest to the color of the pH strip.
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Remember that on the pH scale of 1 to 12, a solution with a pH of 7 is neutral, a solution with a pH of 1 is strongly acidic and a solution with a pH of 12 is strongly basic. A solution with a pH of 8, therefore, would be weakly basic and a solution with a pH of 6 would be weakly acidic.
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References
Resources
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