Question

An initial pH of 4.00, an equivalence point at pH 9.35 and a moderately short, nearly vertical middle section correspond to a titration curve for _____

a) strong acid titrated by strong base
b) strong base titrated by strong acid
c) weak acid titrated by strong base
d) weak base titrated by strong acid
e) weak acid titrated by weak base

Answer 1

The titration curve with an initial pH of 4.00 and an equivalence point at pH 9.35 indicates that a weak acid is being titrated by a strong base, which corresponds to option c).

Step-by-step explanation:

The character of the titration curve provided, with an initial pH of 4.00 and an equivalence point at pH 9.35, suggests that a weak acid is being titrated by a strong base. In a titration of a strong acid by a strong base, the equivalence point would be at pH 7. However, since the given equivalence point pH is greater than 7, this indicates the formation of a weakly acidic or neutral product which is typical for a titration involving a weak acid and a strong base.

The moderately short and nearly vertical middle section of the curve is also characteristic of weak acid-strong base titrations, where there is a rapid increase in pH near the equivalence point. Consequently, we can identify the titration curve as corresponding to option c) weak acid titrated by strong base.