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pH Calculation Formula:
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pH and pOH are logarithmic measures of the acidity and basicity of aqueous solutions. pH represents the hydrogen ion concentration, while pOH represents the hydroxide ion concentration. At 25°C, they are related by the equation: pH + pOH = 14.
The calculator uses the simple formula:
Where:
Explanation: This relationship holds true for all aqueous solutions at 25°C, allowing easy conversion between pH and pOH values.
Details: pH calculation is essential in chemistry, biology, environmental science, and many industrial processes. It helps determine the acidity or basicity of solutions, which affects chemical reactions, biological functions, and material properties.
Tips: Enter the pOH value (between 0 and 14) in the input field. The calculator will automatically compute the corresponding pH value. The relationship is valid at standard temperature of 25°C.
Q1: Why is the sum of pH and pOH equal to 14?
A: This relationship comes from the ion product of water (K_w = [H⁺][OH⁻] = 1.0 × 10⁻¹⁴ at 25°C). Taking negative logarithms gives: pH + pOH = 14.
Q2: Does this relationship hold at temperatures other than 25°C?
A: No, the ion product of water changes with temperature. At different temperatures, the sum pH + pOH equals -log(K_w), which varies from about 14.9 at 0°C to 13.6 at 60°C.
Q3: What is considered acidic, basic, and neutral?
A: At 25°C: pH < 7 (acidic), pH = 7 (neutral), pH > 7 (basic). Correspondingly: pOH > 7 (acidic), pOH = 7 (neutral), pOH < 7 (basic).
Q4: Can I calculate pOH from pH using the same formula?
A: Yes, the relationship works both ways: pOH = 14 - pH.
Q5: What are typical pOH values for common substances?
A: For example: stomach acid (pOH ≈ 13-14), pure water (pOH = 7), baking soda solution (pOH ≈ 4-5), drain cleaner (pOH ≈ 0-1).