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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 base-10 logarithm of the hydrogen ion concentration. The pH scale typically ranges from 0 to 14, with 7 being neutral.
The calculator uses the pH formula:
Where:
Explanation: The formula calculates the pH value by taking the negative logarithm (base 10) of the hydrogen ion concentration in moles per liter.
Details: pH measurement is crucial in various fields including chemistry, biology, medicine, environmental science, and many industrial processes. It helps determine the acidity or alkalinity of solutions which affects chemical reactions, biological functions, and environmental conditions.
Tips: Enter the 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).
Q1: What is the relationship between pH and [H⁺]?
A: pH and hydrogen ion concentration have an inverse logarithmic relationship. As [H⁺] increases, pH decreases, indicating higher acidity.
Q2: What are typical pH values?
A: Pure water has a pH of 7 (neutral). Acidic solutions have pH < 7, while basic solutions have pH > 7. The pH scale is logarithmic, meaning each whole pH value below 7 is ten times more acidic than the next higher value.
Q3: How precise is pH measurement?
A: Laboratory pH meters can measure pH with precision of ±0.01 pH units. For most applications, pH values are reported to one or two decimal places.
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 exceed 14, though these are not commonly encountered.
Q5: What is pOH and how is it related to pH?
A: pOH is the negative log of the hydroxide ion concentration. In aqueous solutions at 25°C, pH + pOH = 14.