What does it mean to have the pH of a solution equal to zero?
The pH is define in the following way: pH = -log [H+] What that
means is the pH is the negative of the base 10 logarithm of the
concentration of hydrogen ions in the solution. So, if you have a
pH = 0, that means that the concentration of H+ is equal to 1
molar, because -log(1) = 0. If you have a 1 M solution of any
strong acid, the pH will be equal to zero.