Questions: Determine the initial pH of the solution:
Initial pH
Before equivalence point
After equivalence point
Moles H3O+ remaining = (initial moles H3O+) - (moles H2O+ reacted); use
Moles excess OH- present = (moles OH- added) - (moles OH- reacted): total volume to calculate new [H3O+] and pH use total volume to calculate new [ OH-] calculate pH from pOH
[H3O+] = [HA) and pH = -log (H3O+]
Transcript text: Determine the initial pH of the solution:
Initial pH
Before equivalence point
After equivalence point
Moles $\mathrm{H}_{3} \mathrm{O}^{+}$remaining $=$(initial moles $\mathrm{H}_{3} \mathrm{O}^{+}$) - (moles $\mathrm{H}_{2} \mathrm{O}^{+}$reacted); use
Moles excess $\mathrm{OH}^{-}$present $=$(moles $\mathrm{OH}^{-}$added) - (moles $\mathrm{OH}^{-}$reacted): total volume to calculate new $\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]$and pH use total volume to calculate new [ $\mathrm{OH}^{-}$] calculate pH from pOH
\[
\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]=[\mathrm{HA}) \text { and } \mathrm{pH}=-\log \left(\mathrm{H}_{3} \mathrm{O}^{+}\right]
\]
Solution
Solution Steps
To determine the initial pH of the solution, we need to follow a series of steps. Let's assume we are dealing with a simple monoprotic acid, HA, in solution.
Step 1: Determine Initial Concentration of \(\mathrm{H}_3\mathrm{O}^+\)
The initial concentration of \(\mathrm{H}_3\mathrm{O}^+\) is equal to the concentration of the acid, \([\mathrm{HA}]\), because the acid dissociates to produce \(\mathrm{H}_3\mathrm{O}^+\).
Step 2: Calculate \([\mathrm{H}_3\mathrm{O}^+]\)
Assuming complete dissociation of the acid, \([\mathrm{H}_3\mathrm{O}^+]\) is equal to the initial concentration of the acid, \([\mathrm{HA}]\).
Step 3: Calculate Initial pH
The pH is calculated using the formula:
\[
\mathrm{pH} = -\log \left([\mathrm{H}_3\mathrm{O}^+]\right)
\]
Substitute the concentration of \(\mathrm{H}_3\mathrm{O}^+\) into the formula to find the pH.
Final Answer
The initial pH of the solution is \(\boxed{\mathrm{pH} = -\log \left([\mathrm{HA}]\right)}\).