Question

what combination of acid and base does this titration curve represent?

a weak acid titrated with a weak base.
a strong acid titrated with a strong base.
a weak acid titrated with a strong base.
a strong acid titrated with a weak base.

Explanation:

Analyze the initial pH

Using the Titration Curves knowledge point
The titration curve starts at a very low pH, specifically around \(1\). This extremely low initial pH indicates that the analyte in the flask is a strong acid, as weak acids typically start at a higher pH (usually between \(3\) and \(5\)).

Analyze the equivalence point pH

Using the Equivalence Point pH knowledge point
The equivalence point is located at the center of the steepest vertical region of the curve. Looking at the graph, this steep vertical rise occurs between pH \(3\) and pH \(11\), with the midpoint (equivalence point) located exactly at pH \(7\). A neutral equivalence point of \(7\) is characteristic of a strong acid-strong base titration.

Analyze the final pH

Using the Titration Curves knowledge point
As excess titrant is added, the pH levels off at a very high value, around \(13\). This high final pH indicates that the titrant being added is a strong base, as a weak base would level off at a lower pH (around \(10\) to \(11\)).

Determine the combination

Using the Titration Curves knowledge point
Combining the initial pH (strong acid) and the final pH/equivalence point (strong base), the curve represents a strong acid titrated with a strong base.

Answer:

• A weak acid titrated with a weak base.
• A strong acid titrated with a strong base. (Correct answer)
• A weak acid titrated with a strong base.
• A strong acid titrated with a weak base.