sentence2_structure: The concentration of the hydrogen ion in a solution<>can be calculated<>when the ph is known$$$the ph<>is known<>
sentence1: pH is the hydrogen ion concentration to the log 10 , and this is the basis of calculation of the pH scale from 1 to 14.
sentence2: The concentration of the hydrogen ion in a solution can be calculated when the ph is known.
question: The concentration of the hydrogen ion in a solution can be calculated when what is known?