Potable water experiment

• you can test and distill water in the lab
• 1. First test the pH of the water using a pH meter. If the pH is too high or too low, you'll need to neutralise it by adding acid (if the pH is high) or alkali (if the pH is low). Use a pH metre to tell you when the solution is between 6.5 and 8.5
• 2. You should also test the water for the presence of sodium chloride (main salt in seawater)

  • To test for sodium ions, do a flame test on a small sample, if they are present the flame will turn yellow
  • To test for chloride ions, take another sample your water and add a few drops of dilute nitric acid, followed by a few drops of silver nitrate solution. If they are present, a white precipitate will form
• 3. To distil the water, pour the salty water into a distillation apparatus. Heat the flask from below, the water will boil and form steam, leaving any dissolved salts in the flask. The steam will condense back into liquid water in the condenser and can be collected as it runs out
• 4. The, retest the distilled water for sodium chloride to check that it has been removed. Also retest the pH of the water with a pH meter to check that its between pH 6.5 and 8.5