The pH scale is a numerical scale used to measure how acidic or basic (alkaline) a solution is. It tells us the concentration of hydrogen ions present in the solution.
Key Points:
- The scale usually ranges from 0 to 14.
- A pH of 7 is considered neutral (pure water is an example).
- A pH less than 7 indicates an acidic solution (more hydrogen ions).
- A pH greater than 7 indicates a basic or alkaline solution (fewer hydrogen ions, more hydroxide ions).
- The scale is logarithmic, meaning each step represents a tenfold change in acidity or basicity.
Examples:
- Lemon juice has a low pH (acidic).
- Soap solution has a high pH (basic).
- Distilled water has a pH close to 7 (neutral).
In simple words: the pH scale is a yardstick for acidity and alkalinity, helping us understand whether a substance is acidic, neutral, or basic.