Home
Back
pH Equation:
| From: | To: |
The pH = -log[H⁺] equation is a fundamental formula in chemistry that calculates the pH (potential of Hydrogen) of a solution based on the concentration of hydrogen ions. It provides a logarithmic measure of acidity or alkalinity.
The calculator uses the pH equation:
Where:
Explanation: The equation converts the hydrogen ion concentration to a logarithmic scale, making it easier to work with the wide range of concentrations found in solutions.
Details: pH measurement is crucial in chemistry, biology, medicine, environmental science, and many industrial processes. It helps determine the acidity or basicity of solutions and is essential for understanding chemical reactions and biological processes.
Tips: Enter hydrogen ion concentration in mol/L. The value must be greater than 0. For very small concentrations, scientific notation may be helpful (e.g., 1e-7 for 0.0000001 mol/L).
Q1: What is the pH scale range?
A: The pH scale typically ranges from 0 to 14, with 7 being neutral. Values below 7 indicate acidity, and values above 7 indicate alkalinity.
Q2: What is a normal pH for drinking water?
A: Drinking water typically has a pH between 6.5 and 8.5. The EPA recommends a pH between 6.5 and 8.5 for drinking water.
Q3: How does temperature affect pH?
A: The pH of pure water decreases with increasing temperature, but this doesn't mean the water becomes more acidic. The change is due to the temperature dependence of the water dissociation constant.
Q4: Can pH be negative or greater than 14?
A: Yes, for very strong acids, pH can be negative, and for very strong bases, pH can be greater than 14. These are extreme cases with very high concentrations of H⁺ or OH⁻ ions.
Q5: What is pOH and how is it related to pH?
A: pOH = -log[OH⁻] and is related to pH by the equation pH + pOH = 14 at 25°C. This relationship comes from the water ion product constant K_w = [H⁺][OH⁻] = 10⁻¹⁴.