Hydrogen concentration in a solution defines the pH value of the solution.
Solutions with higher hydrogen concentration are acidic and the ones with lower concentrations are alkalne.
In order to determine the pH value of the solution we must use the following formula :
pH = -log (H+)
In our example it would be
-log 0,025= 1,6
This solution has a pH of 1,6 which means is it very acidic.