For the vinegar titration in this experiment, would the following errors cause t
ID: 1055211 • Letter: F
Question
For the vinegar titration in this experiment, would the following errors cause the% acetic acid in vinegar determined to be (A) too large, (B) too small, (C) no effect, or (D) not enough information to answer. Assume that the mistake given is the only mistake made in the experiment. Explain. The beret is rinsed with distilled water, but not NaOH solution before the vinegar sample is titrated. After standardization, the NaOH solution is not stoppered and absorbs CO: (from the air) before titration is carried out. The vinegar sample absorbs CO_2 from the air before titration is carried out. The endpoint is too pink during standardization of the NaOH solution. The endpoint is too pink during titration of the vinegar solution. The flask is not dry when the vinegar solution is added into it.Explanation / Answer
Experimental errors and effect on the percent acetic acid in vinegar
- When the buret is rinsed with water but not NaOH : (A) Too large
The NaOH would get diluted with water present in buret and we would end up using excess NaOH (now dilute) for titration.
- NaOH solution was not stoppered after standarisation : (A) Too large
NaOH gets diluted with H2O absorbed from air and hence we would use greater NaOH volume for titration.
- Vinegar solution absorbs CO2 : (A) Too large
NaOH would also react with CO2 in solution to form Na2CO3 and thus greater volume of NaOh would be used.
- End point is standarisation of NaOH was too pink : (B) Too low
The reslting NaOH molarity is calculated low and so low moles of acetic acid would be obtained by this.
- End point of vinegar titration was too pink : (A) Too high
More NaOH was added, higher moles of acetic acid.
- The flask is not dry when vinegar is added : (C) no effect
Moles of vinegar remains unaffected.