Question

Suppose the pH of a solution decreases by 9. How does the hydrogen ion concentration​ change?

Answer 1

hydrogen ion increases

Explanation:

as the pH value decreases, the molecule becomes more acidic in nature. and a solution can be termed base when it contains OH-, and an acid when it contains a H+ ion.

the now formed solution will have attained 9 more H+ ions

Answer 2

im pretty sure the answer would be hydrogen ion increases