Final answer:
To determine the concentration of hydroxide ions from a solution with a pH of 8.73, calculate the pOH by subtracting the pH from 14, then find the concentration by taking the antilog of the negative pOH value. The hydroxide ion concentration is 5.37 × 10⁻¶ M.
Step-by-step explanation:
To find the concentration of hydroxide ions [OH⁻] in a solution with a pH of 8.73, you first need to calculate the pOH. Using the relationship pH + pOH = 14 at 25 °C, you can determine the pOH:
pOH = 14 - pH = 14 - 8.73 = 5.27
Then, using the definition of pOH, where pOH = -log[OH⁻], we can find the concentration of hydroxide ions:
[OH⁻] = antilog (-pOH) = antilog (-5.27)
By applying the antilog function on a calculator:
[OH⁻] = 10⁻²ˣ⁷ M = 5.37 × 10⁻¶ M
Therefore, in a basic solution with a pH of 8.73, the hydroxide ion concentration is 5.37 × 10⁻¶ M.