Calculate the hydroxide ion concentration in an aqueous solution with a pH of 9.85 at 25°C. A) 7.1 × 10^-5 M B) 4.2 × 10^-10 M C) 8.7 × 10^-10 M D) 6.5 × 10^-5 M E) 1.4 × 10^-10 M

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Quizplus · Accepted Answer

The hydroxide ion concentration [$\text{OH}^-$] in an aqueous solution can be calculated using the relationship between pH and pOH, where $pH + pOH = 14$ at 25°C. Given a pH of 9.85, the pOH is $14 - 9.85 = 4.15$. The concentration of hydroxide ions can then be found using the formula $[\text{OH}^-] = 10^{-pOH}$, which gives $[\text{OH}^-] = 10^{-4.15} \approx 7.1 \times 10^{-5} M$.

Calculate the Hydroxide Ion Concentration in an Aqueous Solution with a PH