Question

As the [ H3O+] in a solution decreases , the [ OH -]
A) Increases and Ph increases
B) Increases and the PH decreases
C) decreases and the PH increases

Answer 1

 As the [H3O+]  in  a solution decrease, the [OH-]  increase and Ph increase ( answer A)

explanation

[H3O +]      are  released  by an acid while [OH-]    are released  by base.

The Ph of  an  acid is below 7  while that of a base is above 7.

as [H3O+] is decreased in solution  [OH-]  is increased   which make the solution more basic hence the PH is  increrased.