Experiment Eleven: Preparation and Standardization of a Sodium Hydroxide Solution Aim: The purpose of this experiment is to standardize a solution of sodium hydroxide by titration with a primary standard potassium hydrogen phthalate KHP. Materials Used: A pipette, a funnel, NaOH KHP, distilled water, a burette, three beakers, weighing paper, an analytical balance, and distilled water. In this experiment we determined the concentration of a sodium hydroxide solution to a high degree of accuracy. This process is called standardization and the resulting solution is a standard solution.
That is, a standard solution is one having an accurately known concentration. In order to determine the concentration of the sodium hydroxide solution, one must have an especially pure acid so that an accurately measured amount of acid can be weighed out on the analytical balance. The weight of this acid is the starting point for all subsequent calculations and it is therefore called the primary standard. When the titration of KHP with NaOH occurs the base turns the solution permanently pink. We continue to conduct this experiment three times and recording the reading on the data sheet. Thus we are able to calculate the normality of the NaOH solution by multiplying the weight of KHP by 204.20 and dividing it by the volume of NaOH used. The average normality of the NaOH solution was measured to be .1029 N. In reference to the instructions carried out and any deviations from the manual, it is important to note that our class used a smaller amount of material in regards to the amount designated from the lab manual. Possible sources of error may be reading the balance or the buret incorrectly.
The buret must also run clean and if there are any air bubbles under the stopcock it will skew the results. Recording the weight of the paper and KHP could have resulted in incorrect measurements if someone is leaning on the analytical balance table or the numbers are not recorded four decimal places to the right in order to indicate a more accurate reading. Lastly, another source of error can occur through spillage splashing or splattering of the material when titrating the KHP solution with NaOH.
