Home

Home
Common Compounds
Exam Guide
FAQ
Features
Glossary
Construction Kits
Companion Notes
Just Ask Antoine!
Simulations
Slide Index
Toolbox
Tutorial Index

FAQ
Introduction
Measurement
Matter
Atoms & ions
Compounds
Chemical change
The mole
Gases
Energy & change
The quantum theory
Electrons in atoms
The periodic table
Chemical bonds
Solids
Liquids
Solutions
Acids & bases
Redox reactions
Reaction rates
Organic chemistry
Everyday chemistry
Inorganic chemistry
Environmental chemistry
Laboratory
History of chemistry
Miscellaneous


Home :FAQ :Acids and basesPrint | Comment
Previous Question Next Question

How is [H+] found from pH?

How do you determine concentration of hydrogen ions when given the pH of a solution?
Mamuke, Illinois State University

Vocabulary
pH*
molarity*
A simple, working definition of pH is [1]

pH = - log[H+]

To obtain the hydrogen ion molarity from the pH, remember that a logarithm of a number is really just the exponent when that number is written as a power of ten:

x = 10log x
so the definition of pH solved for hydrogen ion molarity is
[H+] = 10-pH
For example, the molarity of hydrogen ions in a pH 5 solution is 10-5 M.

Notes

  1. pH is only approximately equal to minus the log of the hydrogen ion molarity. For details, see "What is pH?"

Author: Fred Senese senese@antoine.frostburg.edu



General Chemistry Online! How is [H^+^] found from pH?

Copyright © 1997-2010 by Fred Senese
Comments & questions to fsenese@frostburg.edu
Last Revised 02/23/18.URL: http://antoine.frostburg.edu/chem/senese/101/acidbase/faq/molarity-and-pH.shtml