Final answer:
To determine the concentration of hydroxide ions in a 0.100 M HF solution, one would typically need to know the dissociation constant of HF or the pH of the solution. By finding the pH, we can calculate pOH and then use the pOH to determine [OH-], which will be less than 1 × 10^-7 M for an acidic solution.
Step-by-step explanation:
To find the concentration of hydroxide ions (OH-) in a 0.100 M solution of HF, hydrofluoric acid, we need to use the autoionization constant of water, Kw, which is 1.0 × 10-14 M2 at 25 °C. The concentration of hydronium ions (H3O+) for HF can be calculated using its dissociation constant (Ka) and the initial concentration of HF, but since Ka isn't provided in the question, we'll approach the problem by finding the pH of the solution and then the corresponding pOH and [OH-].
First, determine the pH using a pH meter or calculation based on the dissociation constant of HF. Then, convert pH to pOH by subtracting the pH from 14 (since pH + pOH = 14). Lastly, calculate [OH-] by using the formula pOH = -log[OH-], which can be rearranged to [OH-] = 10-pOH. Remember to report the result to three significant figures.
We cannot provide the exact [OH-] concentration without additional information such as the Ka value for HF or the measured pH of the solution. But in general, for an acidic solution with pH less than 7, the concentration of OH- will be less than 1 × 10-7 M.