#
PH Basics

- 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.

- 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