Final answer:
The hydroxide ion concentration ([OH-]) in a solution with a pH of 2.63 is found by first calculating the hydronium ion concentration ([H3O+]) as 10^-2.63 M and then using the ion product of water (kw) to determine [OH-] as kw divided by [H3O+].
Step-by-step explanation:
The lab question asks about calculating the hydroxide ion concentration (represented as [OH-]) when the pH of an acidic solution is given as 2.63. To find the hydroxide ion concentration, we can use the relationship between the concentrations of hydronium ions ([H3O+]) and hydroxide ions in water at 25 °C, which is kw = [H3O+][OH-] = 1.0 × 10-14.
First, we convert pH to [H3O+] by using the formula [H3O+] = 10-pH. Then we use the relationship to solve for [OH-].
pH = -log[H3O+]
The pH of the solution is 2.63, so we can calculate [H3O+] as follows:
[H3O+] = 10-2.63 M.
Now we can calculate [OH-] using the relationship:
[OH-] = kw / [H3O+]
[OH-] = 1.0 × 10-14 / 10-2.63 M.
To determine whether the solution is acidic or basic, we look at the relative sizes of [H3O+] and [OH-]. A solution is acidic if [H3O+] > [OH-], which would be the case here given the low pH.