Questions: Which step of the titration curve uses the given calculations to determine the pH ? After the equivalence point At the half-equivalence point At the equivalence point Before any titrant is added

Which step of the titration curve uses the given calculations to determine the pH ?
After the equivalence point
At the half-equivalence point
At the equivalence point
Before any titrant is added

Transcript text: Which step of the titration curve uses the given calculations to determine the pH ? After the equivalence point At the half-equivalence point At the equivalence point Before any titrant is added

Solution

Solution Steps

Step 1: Analyze the given information

The given calculation states that $\mathrm{pOH} = \mathrm{pK_b}$ because $[B] = [\mathrm{HB}^+]$. This condition is met at the half-equivalence point of the titration of a weak base with a strong acid.

Step 2: Relate the condition to titration steps

At the half-equivalence point, half of the weak base has been neutralized by the strong acid, forming its conjugate acid. At this point, the concentrations of the weak base ($[B]$) and its conjugate acid ($[\mathrm{HB}^+]$) are equal.

Step 3: Determine the corresponding step

Since the given condition occurs at the half-equivalence point, the calculations are used to determine the pH at the half-equivalence point.