There is no such thing as "pHO." It's likely a typo.

pH is the measure of the acidity or alkalinity of a solution. It is calculated using the following formula:

pH = -log[H+]

where:

* pH is the potential of hydrogen, a measure of acidity or alkalinity.

* log is the logarithm to the base 10.

* [H+] is the concentration of hydrogen ions in moles per liter (mol/L).

Note: The pH scale ranges from 0 to 14.

* pH < 7 indicates an acidic solution

* pH = 7 indicates a neutral solution

* pH > 7 indicates an alkaline (basic) solution