The pH Scale
Importance of the pH Level
Swimming pools are often treated with hypochlorous acid (HClO) to prevent the growth of algae and bacteria. The pH of water in these pools must therefore be maintained between 7.2 and 7.4. At a lower pH, pool water can cause eye irritation.
Note the pH level of common fluids in the table.
| Fluids | pH Value |
|---|---|
| Lemon juice | 2.4 |
| Vinegar | 3.0 |
| Orange juice | 3.5 |
| Urine | 4.8 -7.5 |
| Saliva | 6.4 -6.9 |
| Milk | 6.5 |
| Pure water | 7.0 |
| Blood | 7.35 -7.45 |
| Tears | 7.4 |
| Milk of magnesia | 10.6 |
| Household ammonia | 11.5 |
