DRAFT: This module has unpublished changes.

Data Analysis:


Average concentration of the HCl Solution: 0.09081 M

 

Conclusion:

The goal of this experiment is to learn how to properly standardize an acidic solution of which we do not know the exact concentration. By titrating the unknown solution with a standardized titrant, one can then use the data gathered by this to calculate exactly how much titrant was needed to reach equilibrium, and many moles of the titrant were required to completely react with the solution of unknown concentration. By taking the stoichiometric ratios of these compounds into account, one can then calculate the concentration of the unknown solution by using the formula:

 

Average concentration of the HCl Solution: 0.09081 M

As one began with an expected concentration of 0.099 M (given that one began with 16.5 mL of a 6 M solution, and diluted it to 1 L, with deionized water), given the resulting average experimental concentration of 0.09081 mol/L, this indicates error within the experiment that should be further examined.

Trial 1: 9.63%

Trial 2: 9.18%

Trial 3: 5.99%

 

Possible sources of error include:

  • Failure to properly measure (or standardize) the concentration of the NaOH solution.
  • Failure to titrate beyond the equivalence point (making determining the point at which the two solutes had completely reacted impossible).
  • Failure to keep the solution mixed while titrating, introducing the possibility that the solution may not completely react in areas, and the possibility of inaccurate measurement.
  • Failure to properly flush the titrator before beginning the experiment, either contaminating the solution, or diluting it with residual deionized water.
  • Failure to properly handle the solutions, introducing the likelihood of contamination (NaOH can react with carbon dioxide in the air, while the HCl can leave solution, and return to its gaseous state), thus disrupting measurements.
  • Human error is always in effect, given that the laboratory does not function under ideal conditions. As such, there is always the possibility of inaccuracies with measurement, perception of measurement, inaccuracies of equipment, and other such errors. (However, this is not likely to be the sole cause of the inaccuracies within this experiment, though it may contribute to it.)

 

Possible improvements that one could make to the experiment include using a more accurate pH probe, using more accurate balances (relating back to Lab 6a, and the standardization of the NaOH titrant), using a more accurate titrator (the syringe could be made more accurate), ensuring that lab partners read the experiment beforehand (increasing familiarity with the procedure, and minimizing human error), preparing the solutions in an atmosphere that lacks carbon dioxide (to avoid reaction of the NaOH solution), keeping the HCl solution covered (to minimize inaccuracies caused by it leaving solution) and repeating the experiment multiple times (to minimize the impact of an anomalous result).

DRAFT: This module has unpublished changes.