1. An aqueous solution of weak base B of unknown concentration is tritrated with a

Question

known concentration of strong acid, HA.

(a) Write the balanced chemical equation for this acid-base reaction, identifying the
conjugate acid/base pairs.

(b) If the base-dissociation constant of B is 1 × 10^3, what is the pH at the midpoint
of the buffer region? What are the chemical components of the buffer?

(c) Write the balanced chemical equation for the weak acid dissociation in water
occurring at the equivalence point.

(d) At the equivalence point, 500mL of 0.2 M HA(aq) was added to 500mL of the
original B(aq) solution. What is the pH at the equivalence point?

(e) Sketch the titration curve, labeling all axes, the bu?er region, and equivalence
point, along with corresponding pH values.

Answer 1

HA + B ==> BH^+ + A^-
conjugate pairs are as follows:
HA/A^-
B/BH^+

You made a typo on (b). A Kb of 1E3 is NOT a weak base. Therefore, the rest of the problem flawed and the numbers won't mean anything. However, when you correct the Kb value, use the Henderson-Hasselbalch equation to work the buffer part of the problem.