Answer:
c. Its pH value decreases.
Step-by-step explanation:
Remember that hydronium ions are represented by H3O (+), the concentration of this will be used in the concentration of protons H (+) and the formula of pH is the following:
If the concentration of H (+) increases, the pH will decrease. You can check this matematically. And when the concentration of H (+) decreases, the pH will increase. So the answer would be c. Its pH value decreases.