pH Calculator

Easily calculate pH, pOH, H⁺ ion and OH⁻ ion concentrations of solutions. Also supported for weak and strong acids/bases.

Select Calculation Method

Calculate pH/pOH

Please select and enter the known value you want to calculate:

Calculate others from pH value Calculate others from pOH value Calculate from [H⁺] concentration Calculate from [OH⁻] concentration Calculate from Acid/Base concentration

pH Value:

pOH Value:

[H⁺] Concentration (mol/L):

[OH⁻] Concentration (mol/L):

Fill in only the input field you selected, leave the others blank. Ka/Kb values are not required for strong acids/bases.

What is pH?

**pH**, bir çözeltinin asitliğini veya bazlığını (alkaliliğini) ifade eden bir ölçektir. Sudaki hidrojen iyonu ($ H^+ $) konsantrasyonunu logaritmik olarak belirtir.

The pH scale generally ranges from 0 to 14:

**pH < 7:** Acidic solution
**pH = 7:** Neutral solution (pure water)
**pH > 7:** Basic (alkaline) solution

The formula for pH is as follows:

$ pH = -\log_{10}[H^+] $

Burada, $ [H^+] $ çözeltideki hidrojen iyonu konsantrasyonunu (mol/L cinsinden) ifade eder.

What is pOH?

**pOH**, bir çözeltinin bazlığını gösteren bir ölçektir ve hidroksit iyonu ($ OH^- $) konsantrasyonuna bağlıdır:

$ pOH = -\log_{10}[OH^-] $

At 25°C, the relationship between pH and pOH is:

$ pH + pOH = 14 $

Relationship Between Ion Concentrations and pH:

Conversions can be made between hydrogen and hydroxide ion concentrations (mol/L) and pH/pOH:

$ [H^+] = 10^{-pH} $
$ [OH^-] = 10^{-pOH} $
25°C'de suyun iyon çarpımı sabiti ($ K_w $): $ [H^+][OH^-] = 1.0 \times 10^{-14} $

Strong and Weak Acids/Bases

**Strong Acids/Bases:** Completely ionize in water. Therefore, the H⁺ or OH⁻ concentration of the solution is equal to the initial concentration of the acid/base (if monoprotic).
**Zayıf Asitler/Bazlar:** Suda kısmen iyonlaşırlar ve dengeye ulaşırlar. Bu durum için asit ayrışma sabiti ($ K_a $) veya baz ayrışma sabiti ($ K_b $) değerleri kullanılır.
Zayıf Asitler için: $ K_a = \frac{[H^+][A^-]}{[HA]} $

Zayıf Bazlar için: $ K_b = \frac{[BH^+][OH^-]}{[B]} $

Zayıf Asit pH (Yaklaşık): $ [H^+] \approx \sqrt{K_a \cdot C_a} $

Zayıf Baz pOH (Yaklaşık): $ [OH^-] \approx \sqrt{K_b \cdot C_b} $

Application Areas:

**Health and Medicine:** The pH balance of body fluids (blood, urine) is of vital importance.
**Food Industry:** The quality, safety and shelf life of foods depend on pH.
**Environmental Science:** The pH of soil and water affects ecosystem health and the behavior of pollutants.
**Agriculture:** Soil pH is critical for plant growth and nutrient uptake.
**Chemical Industry:** The rate and efficiency of many chemical reactions depend on pH.

This calculator performs basic pH/pOH and ion concentration calculations for ideal solutions at 25°C. In weak acid/base calculations, the equilibrium constant (Ka/Kb) is required and a simple approximation (squaring) is often used. In real-world applications, temperature, ionic strength, and other chemical interactions can affect pH. More complex scenarios require advanced chemical modeling and experimentation.