The graph below shows the pH changes during the titration of a weak acid with so

Question

The graph below shows the pH changes during the titration of a weak acid with sodium hydroxide (NaOH). Based on the titration curve, determine the pK_a of the acid. Find the half-equivalence volume on the titration curve. The half-equivalence port is the point at which half the volume of base required to reach equivalence has been added. For the titration shown, _______ mL of NaOH is required to neutralize the acid and reach equivalence Therefore, the half-equivalence port occurs when half this volume of base, _______ mL, has been added. Find the pH at the half-equivalence point (Enter your answer to one decimal place to account for the precision of the values on the x and y-axes.) Find the pH of the titration solution at the half-equivalence point. Trace a vertical line from the 15 mL point on the x-axis up to the curve From there, trace a horizontal line to the y-axis to find the pH, which is approximately _______. At the half-equivalence point, the pH is equal to the pK_a of the acid. This can be shown by examining the Henderson-Hasselbalch equation and the dissociation of the acid. At the half-equivalence point, the concentrations of dissociated acid (A^-) and undissociated acid (HA) are equal. Therefore, the ratio of their concentrations is 1 and the logarithm of 1 is 0, eliminating the right-hand term in the equation. This leaves pH = pK_a. HA + H_2O Equilibrium H_3O^+ + A^- pH = pK_a + log [A^-]/[HA] Therefore, the pH at the half-equivalence port is equal to the pK_a of the acid, which is - _______.

Explanation / Answer

step 2:

all the procedure are well written. from the plot it is clear that this is titration curve of weak monobasic acid with strong base NaOH. From the plot the value of pH will be 3.75 ( but the answer will be 3.7 in one decimal factor)

according to Henderson-Hasselbatch equation....pKa will be equal to pH

hence, pH will be 3.75

[from pKa value it can be said that the acid will be formic acid]

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.