Yes, pH can be negative. This occurs when the concentration of hydrogen ions (H+) in a solution is greater than 1 mol/L. The pH scale is calculated using the formula:
pH = -log[H+]
where [H+] is the molar concentration of hydrogen ions.
When the concentration of hydrogen ions exceeds 1 mol/L, the logarithm becomes negative, resulting in a negative pH value.
Here are some examples of situations where a negative pH might occur:
- Strong acid solutions: Concentrated solutions of strong acids like hydrochloric acid (HCl) or sulfuric acid (H2SO4) can have negative pH values.
- Superacids: Superacids are extremely strong acids that are far stronger than traditional mineral acids. They can have pH values significantly lower than 0.
However, it's important to note that not all pH probes can accurately measure negative pH values. Some probes may have a limited measurement range, while others may be affected by the high concentration of hydrogen ions in extremely acidic solutions.
