The following erroneously high molarities were measured for a NaOH solution, whi
ID: 510950 • Letter: T
Question
The following erroneously high molarities were measured for a NaOH solution, which is known to have a molarity of 0.2500 M: 0.2552 0.2550 0.2554 Which one of the following experimental errors is most likely affecting this analysis? Explain your answer briefly. (a) NaOH titrant was prepared from water with a high concentration of carbon dioxide. (b) An improperly calibrated balance, causing KHP masses to appear larger than actual. (c) Randomly erratic end points. (d) Spattering of only one sample solutions during titration but before the end point. (e) Buret reading uncertainty caused by parallax.Explanation / Answer
It is observed that all the calculated three values are higher in strength with respect to the true value.
if NaOH prepared in water having high concentration of carbon di oxide, then the calculated values should be less. because, in presence of carbon di oxide, water will form carbonic acid which can decrese the strength of NaOH instantly and in all the calculated three values should same. therefore, option a will not affecting the analysis.
option c and e are the human errors ,If it is true, the the calculated values have the possibilities either more or less than actual values, therefore, these two options will not affecting the analysis.
spattering of KHP will increase the strength of NaOH but reverse case it will not change the strength of NaOH because strength is calculated based on V1S1 = V2S2 formula.
so option b will be most likely affecting the analysis. Because calculation will shows KHP is stronger than true strength due to improperly calibrated balance. therefore, required volume of NaOH will be less then the true volume.
hence, option b will the right answer.
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