What is the relationship between the concentration of the hydronium and hydroxide ion and pH in any water solution?

The concentration of hydronium ions and the pH value is related by the equation: pH=-Log[H+]

Explanation:

We have two different concepts pH and concentration of hydronium ions. Lets start with the hydronium ion.

An hydronium ion is a species that is produced by an acid:

Aditionally, we can have the production of hydroxide ions. The subtances that have the capacity to produce this ions are called "bases":

Now we can continue "pH"

The pH is a scale that indicates if the substance is and acid (higher concentration of ), neutral (equal amounts of and ) or basic (higher amount of ).

Finally, the "pH" is calculated with the concentration of the hydronium ions (

), the letter "p" is "-Log", therefore:

I hope it helps!