Question

Consider the titration curve describing the titration of a strong acid by addition of a strong base. Which of the following statements is false?

a. the equivalence point is at pH=7.0
b. the pH is lower at the end of the titration than at the beginning
c. the pH increases rapidly around the equivalence point
d. at the equivalence point, the only species present are water and a neutral salt
e. the pH does not increase very rapidly at the beginning of the titration

Answer 1

The false statement is that the pH is lower at the end of the titration than at the beginning. During a strong acid-strong base titration, the pH initially increases slowly, rises rapidly around the equivalence point, and then increases more slowly again, ending at a higher pH.

Step-by-step explanation:

Considering the titration curve describing the titration of a strong acid by addition of a strong base, the statement that is false is that "the pH is lower at the end of the titration than at the beginning."

During a titration of a strong acid with a strong base, the pH at the equivalence point is typically 7.0 because the moles of acid and base are equal and they neutralize each other. This results in the formation of water and a neutral salt. Initially, the pH increases very slowly as base is added. It is only near the equivalence point that the pH rises rapidly due to most of the H+ ions being consumed. After the equivalence point, the pH continues to rise but at a slower rate again. Consequently, at the end of the titration, the solution is more basic, and thus the pH is higher, not lower, than at the beginning.