## pH

It is inconvenient to express concentration of hydrogen ions as a number with
many zeros right after the decimal point,
e.g., H^{+} = 0.00000048 N.
Instead we define pH as the negative logarithm of the hydrogen ion
concentration, and the clumsy number just used becomes pH = 6.32. Pocket
calculators convert concentration to pH merely by entering the concentration,
invoking the logarithm (base 10) function, and changing the sign. The
reverse operation requires entering the pH, raising ten to that power, and
taking the reciprocal.

**NEXT**

**Back to outline**