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pH Formula:
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pH is a measure of the acidity or basicity of a solution. It is defined as the negative logarithm (base 10) of the hydrogen ion concentration. The pH scale ranges from 0 to 14, with 7 being neutral, values below 7 acidic, and values above 7 basic.
The calculator uses the pH formula:
Where:
Explanation: The pH value decreases as hydrogen ion concentration increases, indicating higher acidity. Each unit change in pH represents a tenfold change in hydrogen ion concentration.
Details: pH measurement is crucial in various fields including chemistry, biology, environmental science, medicine, and industry. It helps determine the acidity or basicity of solutions, which affects chemical reactions, biological processes, and product quality.
Tips: Enter the hydrogen ion concentration in moles per liter (M). The value must be greater than 0. For very small concentrations, scientific notation may be used (e.g., 1e-7 for 0.0000001 M).
Q1: What is the pH of pure water?
A: Pure water has a pH of 7 at 25°C, which is considered neutral. This corresponds to a hydrogen ion concentration of 1 × 10⁻⁷ M.
Q2: How does temperature affect pH?
A: The pH of neutral water changes with temperature due to the temperature dependence of the water dissociation constant. At higher temperatures, neutral pH is slightly less than 7.
Q3: What is the relationship between pH and pOH?
A: pH + pOH = 14 at 25°C. pOH is calculated as -log[OH⁻], where [OH⁻] is the hydroxide ion concentration.
Q4: Can pH be negative or greater than 14?
A: Yes, for very concentrated strong acids, pH can be negative, and for very concentrated strong bases, pH can be greater than 14. However, these are extreme cases.
Q5: How accurate is this calculation?
A: This calculation provides the theoretical pH based on hydrogen ion concentration. In practice, actual pH measurements may vary due to temperature, ionic strength, and other factors affecting activity coefficients.