Final answer:
To find the pH of a solution with a hydronium ion concentration of 8.45 x 10^-4 M, you take the negative logarithm of the concentration, yielding a pH of approximately 3.073.
Step-by-step explanation:
To calculate the pH of a solution when given the concentration of hydronium ions [H3O+], you need to use the pH formula: pH = -log [H3O+]. In the question, the hydronium ion concentration is given as [H3O+] = 8.45 x 10-4 M. Therefore, to find the pH, you take the negative logarithm of the hydronium ion concentration.
pH = -log (8.45 x 10-4)
Using a calculator, you get:
pH = -(-3.073) = 3.073
Thus, the pH of the solution is approximately 3.073.