moles of NaOH = 0.250 * 1.2 * 10^-3 = 3 * 10^-4 M [NaOH] = [OH-] = 3 * 10^-4 / 1.5 = 2 *10^-4 M pH = - log [H+] [H+] = 10^-14 / [OH-] = 5 * 10^-11 pH = 10.3 Solution moles of NaOH = 0.250 * 1.2 * 10^-3 = 3 * 10^-4 M [NaOH] = [OH-] = 3 * 10^-4 / 1.5 = 2 *10^-4 M pH = - log [H+] [H+] = 10^-14 / [OH-] = 5 * 10^-11 pH = 10.3.