Can pH be below 0 or above 14?

Yes, concentrated solutions can fall outside the 0 to 14 classroom range.

Does this handle weak acids or buffers?

No. Use this page for direct concentration relationships and simple strong acid/base dilution.

Convert between pH, pOH, [H+], and [OH-], or estimate pH after a simple acid or base dilution.

Answer

3

pH

pOH: 11

[H+]: 0.001 M

[OH-]: 1.0000e-11 M

Classification: Acidic

Mode

Known valueValue

Quick values

Examples

Assumes 25 C water where pH + pOH = 14 and concentration approximates activity.

pH = -log10[H+]; pOH = -log10[OH-]; pH + pOH = 14

For simple dilution, the final concentration is C2 = C1 x V1 / V2. The result then uses the direct pH or pOH relationship.

Symbol	Variable	Description
[H+]	Hydrogen ion concentration	Used directly for acid pH.
[OH-]	Hydroxide ion concentration	Used directly for base pOH.
C1, V1, V2	Dilution values	Starting concentration, initial volume, and final volume.

1
Choose a mode
Use direct conversion when you know pH, pOH, [H+], or [OH-]. Use dilution for a simple strong acid or strong base dilution.
2
Enter the known value
Concentrations should be entered in molarity. pH and pOH are unitless.
3
Read all companion values
The answer shows pH first, then pOH, [H+], [OH-], and acidic/basic classification.

Use the pH value to classify the solution under the calculator assumption.

Dilution Calculator

Find the required volume to dilute a chemical stock solution, reagent, buffer, or lab solution.

Molarity Calculator

Find molarity from moles of solute and solution volume.