Which of the following is NOT TRUE?
A. The blank for this experiment must have 100 % transmittance if placed in a spectrometer (Spec 20).
B. The volume required to titrate the blank is subtracted from the volume used to titrate the analyte solution to give the "corrected volume".
C. A blank is titrated to correct for any reactive impurities in the solvent. For this experiment, the impurities would be reducing agents that would react with KMnO4 (mimicking the behavior of C2O42– ).
D. A blank is composed of the solvent used to dissolve the analyte. For this experiment, the solvent is a combination of sulfuric acid, phosphoric acid, and water.
E. All of these are true.
is it E?
You, or someone who copied it exactly as you wrote it, posted this yesterday. I gave that post my best answer and suggested that it would help if you told us the experiment and enough about it to know what you were doing. I also suggested that E was not the right answer and that A probably is the correct one. Blanks need not have 100% T.
The experiment is "analysis of a complex iron salt" . We had a previous lab in which we prepared a complex iron salt and then left it in a dark locker for a week to crystallize. For this upcoming lab, we are weighing .1 g of the complex iron salt and dissolving it and then heating it then titrating it.
If you are titrating it, how is the Spectronic 20 involved?
The answer is definitely A.
To determine which statement is NOT TRUE, we need to evaluate each option and find the one that is false.
Statement A states that the blank for this experiment must have 100% transmittance if placed in a spectrometer (Spec 20). Transmittance refers to the ability of light to pass through a substance. If the blank has 100% transmittance, it means that no light is absorbed, and all light passes through. This statement could be true depending on the experiment requirements.
Statement B mentions that the volume required to titrate the blank is subtracted from the volume used to titrate the analyte solution to give the "corrected volume." In a titration, the blank is used to account for any impurities or reactions that occur in the solvent. This statement is true as the volume of the blank titration is subtracted to obtain the corrected volume.
Statement C explains that a blank is titrated to correct for any reactive impurities in the solvent, specifically reducing agents that would react with KMnO4, mimicking the behavior of C2O42-. This statement is also accurate as the purpose of the blank titration is to take into account any impurities that can affect the analysis.
Statement D states that a blank is composed of the solvent used to dissolve the analyte, consisting of sulfuric acid, phosphoric acid, and water. This could be true if these are the constituents of the solvent used in the experiment.
Therefore, after evaluating all the statements, we find that option E, "All of these are true," is the most accurate answer.