pH scale is used to determine how acidic or basic a solution is. we have been given the hydrogen ion concentration. Using this we can calculate pH, pH = - log[H⁺] pH = - log (1 x 10⁻¹ M) pH = 1 using pH can calculate pOH pH + pOH = 14 pOH = 14 - 1 pOH = 13 using pOH we can calculate the hydroxide ion concentration pOH = - log [OH⁻] [OH⁻] = antilog(-pOH) [OH⁻] = 10⁻¹³ M hydroxide ion concentration is 10⁻¹³ M