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pH and OH- Calculation:
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pH and OH- calculation involves determining the acidity or basicity of a solution using hydrogen ion concentration ([H+]) and hydroxide ion concentration ([OH-]). pH is a logarithmic measure of hydrogen ion concentration, while [OH-] represents hydroxide ion concentration in a solution.
The calculator uses the following equations:
Where:
Explanation: The pH scale ranges from 0 to 14, with 7 being neutral. Values below 7 indicate acidity, while values above 7 indicate basicity. The relationship between [H+] and [OH-] is governed by the water dissociation constant (Kw = 1.0 × 10⁻¹⁴).
Details: Accurate pH and OH- calculations are essential in various fields including chemistry, biology, environmental science, and medicine. They help in understanding chemical reactions, biological processes, water quality assessment, and many industrial applications.
Tips: Enter hydrogen ion concentration in mol/L. The value must be greater than 0. The calculator will automatically compute both pH and [OH-] values.
Q1: What is the relationship between pH and pOH?
A: pH + pOH = 14 at 25°C. pOH is defined as -log10[OH-], similar to how pH is defined as -log10[H+].
Q2: What are typical pH values for common substances?
A: Pure water has pH 7, lemon juice around 2, baking soda solution around 9, and bleach around 13.
Q3: Why is the pH scale logarithmic?
A: The logarithmic scale allows representation of the wide range of hydrogen ion concentrations (from 1 mol/L to 10⁻¹⁴ mol/L) in a convenient 0-14 scale.
Q4: How does temperature affect pH calculations?
A: The water dissociation constant (Kw) changes with temperature, which affects the pH of neutral water and the pH + pOH relationship.
Q5: Can this calculator be used for concentrated solutions?
A: For highly concentrated solutions (>1M), activity coefficients should be considered for accurate pH calculations, as the simple concentration-based approach may not be sufficient.