Multiple Choice
Pyridine, C5H5N, is a weak base with Kb = 1.5 x 10^-9. What is the pH at the equivalence point when 384 mL of 0.78 M pyridine is titrated with 0.78 M HCl?
377
views
18. Aqueous Equilibrium
Titrations: Weak Base-Strong Acid
Multiple Choice
The plot below illustrates which type of titration?
A
a weak acid titrated with a weak base
B
a weak acid titrated with a strong base
C
a strong base titrated with a weak acid
D
a weak base titrated with a strong acid
E
a strong acid titrated with a strong base
Verified step by step guidance1
Examine the initial pH of the solution before any titrant is added. The initial pH is 11.12, which is characteristic of a weak base, such as NH3.
Identify the titrant being added. The x-axis indicates the volume of HCl added, which is a strong acid.
Observe the pH at the half-equivalence point, where the concentration of the weak base equals the concentration of its conjugate acid. The pH at this point is 9.24, which is typical for a weak base titration.
Note the pH at the equivalence point, which is 5.26. This pH is less than 7, indicating that the solution is acidic at the equivalence point, consistent with the titration of a weak base with a strong acid.
Conclude that the titration involves a weak base being titrated with a strong acid, as the initial pH is high, the equivalence point pH is acidic, and the titrant is a strong acid (HCl).
Related Videos
Related Practice
