Question

How does a blank titration reduce titration error?

Answer 1

Hint: The titrant is added to the analyte, the material to be analysed, in a known molar quantity. A known ratio of titrant to the analyte is needed for the reaction to take place, which follows definite stoichiometry.

Complete Step by Step Solution:
1. A pure solvent does not contain any components that might react with the titrant, or provide an estimation of how much the titrant would react with it.
2. This method allows the amount of reactive substance in a plain solvent to be determined, and therefore, an error can be determined for the titration experiments.
3. Titrant is added to no titrant and this allows us to calculate the dead volume of titrant, before the endpoint signals equivalence and this is subtracted from the volume used in the real titration.
4. It's like a background correction in a colorimetric test, except that it also establishes a baseline to which the real sample is compared.
5. For example, a titration of deionized water may be affected by its slight acidity, so the blank titration is performed in order to find out how much \[{H_3}{O^ + }\] is present in the water and then to use that information to adjust the concentration of the analyte.

Additional information:
The value of blank titration is higher than the sample titration:
1. Due to the error in the experimental methodology.
2. Sample has virtually no measured component, and both sample and blank are within expected experimental error.
3. The methodology is different for the blank and sample titration.

Note: The application of blank titration for the analytical determination of a particular substrate that contains a number of reagents and solvents which gives a higher value as compared to a true value. Thus, a blank run without the substrate is performed under the same conditions to deduct from the final result.