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Calculate pH, pOH, and ion concentrations instantly. Perfect for chemistry homework, lab work, and understanding acid-base reactions.
Common substances and their typical pH values
pH = -log₁₀[H⁺]
pOH = -log₁₀[OH⁻]
pH + pOH = 14
[H⁺][OH⁻] = 10⁻¹⁴
[H⁺] = 10⁻ᵖᴴ
[OH⁻] = 10⁻ᵖᴼᴴ
pOH = 14 - pH
pH = 14 - pOH
Get pH, pOH, and ion concentrations in milliseconds
See exactly where your solution falls on the pH spectrum
Calculate from pH, pOH, [H+], or [OH-] concentration
Precise calculations suitable for laboratory work
Quick reference for everyday substances and their pH
Perfect for learning acid-base chemistry concepts
pH is a measure of how acidic or basic a solution is, on a scale from 0 to 14. pH 7 is neutral, below 7 is acidic, and above 7 is basic (alkaline). It's defined as the negative logarithm of hydrogen ion concentration.
pH and pOH are complementary measurements. At 25°C, pH + pOH = 14. If you know one value, you can easily calculate the other by subtracting from 14.
pH affects chemical reactions, biological processes, and material properties. It's crucial in medicine (blood pH), agriculture (soil pH), cooking, water treatment, and countless industrial processes.
The EPA recommends drinking water have a pH between 6.5 and 8.5. Most tap water falls within this range. Very acidic or basic water can corrode pipes and may indicate contamination.
Yes! While rare, concentrated strong acids can have negative pH values, and concentrated strong bases can exceed pH 14. However, the 0-14 scale covers most practical situations.
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