The higher the hydronium ion concentration of a solution, the its ph.

higher or lower

The higher the hydronium ion concentration of a solution, the lower its pH.

                  pH = -log[H+]

For example,

Solution A with a [H₃O+] of 0.003 M will have a pH of

pH = -log 0.003 M

     = 2.52

While, a solution B with a [H₃O+] of 0.025 M will have a pH of

pH = -log 0.25 M

    = 1.60

Therefore, the higher the concentration of hydronium ion of a solution the lower its pH is.

∠gdh and ∠edh on edg.

answer is c