13. The main reason for performing a back titration instead of a direct titration is: A. The reaction is too slow or weak for direct measurement B. It increases the error in the experiment C. It does not require a burette D. The titration curve is always linear
Answer (1)
The main reason for performing a back titration instead of a direct titration is A. The reaction is too slow or weak for direct measurement .
Back titration is commonly used in situations where a direct titration is not feasible. Here are some reasons why back titration is preferred:
Slow or Weak Reactions : Some reactions proceed very slowly or are not well-defined enough to allow for a straightforward direct titration. In such cases, adding an excess amount of a standard solution (the titrant) and then titrating the unreacted excess with another reagent allows for accurate determination of the analyte.
Poorly Soluble Analytes : If the analyte is not soluble enough in the solvent used for a direct titration, a back titration can be used. The analyte is reacted with an excess of a reagent it can dissolve in, and the excess is titrated with a second reagent.
Lack of Suitable Indicators : When there’s no suitable indicator for a direct titration, back titration can be used.
Complexation or Redox Titrations : Back titration is useful in reactions where the product of a direct titration might interfere with the titration process itself.
In summary, back titration is an indirect analysis technique used when the titration cannot be easily measured directly due to reasons like slow reactions or lack of suitable indicators. The chosen option in this multiple-choice question is A .
