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pH Calculation Formula:
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The pH calculation from pOH is based on the fundamental relationship between pH and pOH in aqueous solutions. The sum of pH and pOH always equals 14 at 25°C, which is derived from the ion product of water (Kw = 10⁻¹⁴).
The calculator uses the simple formula:
Where:
Explanation: This relationship holds true for all aqueous solutions at 25°C, making it a fundamental calculation in chemistry.
Details: pH calculation is essential in various fields including chemistry, biology, environmental science, and medicine. It helps determine the acidity or basicity of solutions, which affects chemical reactions, biological processes, and environmental conditions.
Tips: Enter the pOH value (between 0 and 14). The calculator will automatically compute the corresponding pH value. Valid pOH values range from 0 to 14 inclusive.
Q1: Why does pH + pOH always equal 14?
A: This relationship comes from the ion product of water (Kw = [H⁺][OH⁻] = 10⁻¹⁴ at 25°C). Taking negative logarithms gives: -log[H⁺] + -log[OH⁻] = 14, which is pH + pOH = 14.
Q2: Does this relationship hold at temperatures other than 25°C?
A: No, the value changes with temperature because Kw changes. At different temperatures, pH + pOH equals -log(Kw) for that temperature.
Q3: What are typical pH and pOH values?
A: pH and pOH both range from 0 to 14. Acidic solutions have pH < 7 and pOH > 7, basic solutions have pH > 7 and pOH < 7, and neutral solutions have pH = pOH = 7.
Q4: Can I calculate pOH from pH using the same formula?
A: Yes, the relationship works both ways: pOH = 14 - pH.
Q5: When would I need to calculate pH from pOH?
A: This calculation is useful when you have measurements of hydroxide ion concentration and need to find the pH, or when working with problems that provide pOH instead of pH.