Final answer:
To calculate the hydroxide ion concentration in a KOH solution with a given hydronium ion concentration of 3.77 × 10-12M, use the water ion-product constant (Kw) and the formula [OH-] = Kw / [H3O+]. The answer is [OH-] = 2.65 × 10-3 M.
Step-by-step explanation:
The student needs to determine the concentration of hydroxide ions (OH-) in a potassium hydroxide (KOH) solution, given the concentration of hydronium ions (H3O+) is 3.77 × 10-12 M. To calculate [OH-], one should use the ion-product constant for water (Kw) at 25°C, which is 1 × 10-14.
The formula to find [OH-] when [H3O+] is known:
[OH-] = Kw / [H3O+]
Substituting the known values:
[OH-] = (1 × 10-14) / (3.77 × 10-12 M)
Calculations yield:
[OH-] = 2.65 × 10-3 M
So, the concentration of hydroxide ions in the KOH solution is 2.65 × 10-3 M.