Question

Which of the following statements is correct regarding the reason for the need to standardize a titrant? Select one:

A. The acid used as a titrant exists as an aqueous solution, so there is no need to standardize the solution.
B. While weighing, some solids absorb moisture from the air. This contributes to error.
C. Since the titrant is what is being analyzed, you need to standardize it.
D. We need to standardize the aqueous titrant because we only weigh the mass of the dissolved solid; we don't accurately measure how much water is used to prepare the aqueous solution.

Answer 1

The correct answer is B: solids used to prepare titrants may absorb moisture from the air, which contributes to error. Standardization of the titrant ensures its concentration is known and accurate for titration.

Step-by-step explanation:

The correct statement regarding the reason for the need to standardize a titrant is B. While weighing, some solids absorb moisture from the air. This contributes to error. Standardizing the titrant is essential because this ensures that the actual concentration of the titrant solution is known with precision. Since a titration relies on the exact stoichiometry between the titrant and the analyte, any discrepancy in the titrant's concentration can lead to incorrect results. This process becomes crucial when the titrant is prepared by dissolving a solid substance that might have absorbed moisture or when the precise amount of a substance is difficult to obtain.

In a typical acid-base titration, a known concentration of titrant is added to an unknown concentration of analyte until the equivalence point is reached, signified by a color change in the indicator or a measurable change in some property of the solution. The end point is where this change is observed, and the standard solution, which is the titrant with a known concentration, is critical for accurate determination of the unknown concentration in the analyte.

To ensure the accuracy of titration results, the actual concentration of the titrant must be confirmed by titration against a primary standard—a substance with a known purity and stoichiometry—in a process known as standardization.