Which of the following could be the pH of the solution?

The correct answer to this question is 5. The formula for pH is pH = -log[H+]. pH is used in chemistry, to identify how acidic or basic a solution is. This pH would be acidic because 5 is less than 7. Anytime the value is less than 7, and the pH is acidic. If the value were more than 7, the pH would be basic. Along with chemistry, a pH is also important in fields such as medicine and water treatment. The concent of pH came about in 1909 by Soren Peder Lauritz Sorensen, who was a chemist.