This is a Standardization of sodium hydroxide lab let me know if u need more inf
ID: 524683 • Letter: T
Question
This is a Standardization of sodium hydroxide lab
let me know if u need more info
The mass of KHP is measured; however, the exact volume of water in which it is dissolved is never of critical concern. Explain why the addition of water to the flask/beaker is not critical to the analysis, whereas its addition to the NaOH solution is critical. Suppose an air bubble is initially trapped in the buret containing sodium hydroxide. However, during the titration the air bubble is passed from the buret. Will the molar concentration of the sodium hydroxide be reported as too high, too low, or unchanged as a result? Explain. Name two sources of experimental uncertainty in today's lab.Explanation / Answer
1. KHP is neutralised by NaOH but water doesn't enter into the reaction and therefore an accurate measurement isn't needed for the calculations.The concentration of NaOH per unit volume is critical. adding water to the NaOH solution will change the concentration per unit volume. This is not acceptable in volumetric analysis.So, it is important to carefully measure the NaOH volume as the KHP is the measurement to standardize the NaOH. Further, adding too much water, the end point colour change will be less clear and add error to the result.
2. The volume consumed will be more than that of the actual volume. The concentration of NaOH will be lower than the actual result because the titre value is taken in the denominator (in the calculation of strength of sodium hydroxide), we'll get a lower value than the actual result.
3. Instrumental uncertainity - precision of the instrument is important because an instrument has an inherent uncertainity.
Random uncertainity - Sometimes when you measure the same quantity, we may get different results each time we measure it..
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