Final answer:
To calculate the pH of a 3.2 x 10^-4 M solution of NaOH, we use the concentration of OH- ions to find the concentration of H3O+ ions and then calculate the pH using the negative logarithm. The correct answer is A. 10.51.
Step-by-step explanation:
To calculate the pH of a solution of NaOH, we need to find the concentration of H3O+ ions in the solution. Since NaOH is a strong base, it completely dissociates into Na+ and OH- ions. The concentration of OH- ions can be used to calculate the concentration of H3O+ ions using the equation [H3O+] = 10^-14 / [OH-]. In this case, the concentration of OH- ions is 3.2 x 10^-4 M, so the concentration of H3O+ ions is 10^-14 / 3.2 x 10^-4 = 3.125 x 10^-11 M. Taking the negative logarithm of the H3O+ concentration gives the pH: pH = -log(3.125 x 10^-11) = 10.51. Therefore, the correct answer is A. 10.51.