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 In chemistry, pH is a measure of the concentration of hydrogen ions in a solution, which is a measure of acidity or alkalinity.
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?