# PH Basics

Overview |
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- Hydrogen ions (H
^{+}) can exist freely within water solutions, unbound by other molecules. However, fluid concentrations of free H^{+}concentration can range over orders of magnitude, making it inconvenient to write the H^{+}concentration with arabic numerals or even scientific notation. The pH notation was developed as a means of easily indicating the free hydrogen concentration in fluids. The pH of a fluid is related to the base 10 logarithm of its free hydrogen ion concentration. Consequently, the pH scale is not linear and a 1 unit change in pH indicated a 10-fold change in the hydrogen ion concentration.

Derivation |
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- pH = -log
_{10}[H^{+}]

Example |
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- Let us assume that the H
^{+}concentration of a fluid is 4 x 10^{-8}mol/L - Therefore: pH = -log
_{10}[4 x 10^{-8}] - Consequently, the pH of the fluid is pH = 7.4