Answer:
The higher the hydronium ion concentration of a solution, the lower its pH.
Explanation:
Consider a high hydronium concentration, 1 mol·L⁻¹.
pH = -log[H₃O⁺] = -log1 = 0
Now consider a low hydronium ion concentration, 10⁻¹⁴ mol·L⁻¹.
pH = -log(10⁻¹⁴) = 14
Thus, a high hydronium ion concentration means a low pH.
