Acid Weak Titration
Author: Austin Kelly Lab Partners: Maria Ortega, Allison Mensch, John Sanders Lab Supervisor: Wenzhou Li Course: 104B Dates Experiment Performed: Feb. 12 & 19, 2008 Date Report Submitted: 26 February 2008
Abstract In order to determine what the three unknown solutions were, we used the weak acid titration method in order to see what the properties of the unknowns. In order to do this a volumetric kit was used as well as a pH electrode. The Acids were found to be Nitro Benzoic, Formic, and Malic Acid. The titrations went well as the experiment was performed with precision.
Introduction This laboratory experiment is based on the titration of a weak acid (KHP) by the use of the basic solution NaOH. Within the experiment, a titration is used in order to determine the amount of substance present in the solution and be able to neutralize it and even make it into a basic solution using the titration methods. The process of determining the concentration of an unknown solution is known as standardization. We will standardize the solution of NaOH by using a primary standard, which is a material that has a known composition for which accurate weights and volumes can be measured. Using this, we will be able to determine what we will be working with in the respect that it will be reacting with the unknown in certain ways that will help us determine the unknowns definite properties. The techniques that we will be using are quite simple. The tools that we will be using are a few beakers as well as a volumetric kit, which contains all of our appropriate apparatus such as the buret , the volumetric pipet, and the magnetic stir bar. The goal of this lab is to determine the identity of an unknown that solution has been given to us. In the experiment we will be using a pH probe which we must be careful with since the unknown solution that we will be working with is corrosive. We must not let the unknown solution touch the probe as it will destroy the probe.
Discussion
The results that our lab had spit out came to be quite coherent. Although the titration and everything else was pretty hair-splitting, we managed to come to the conclusion of the unknown substances for A2, B2, and C1. For A2, we have decided that the unknown solution was Nitro Benzoic Acid. We determined that the identity of B2 was Malic Acid, and that C1 was Formic Acid. The reason that we came to these results is based solely on our calculations. For A2, we calculated that the molecular weight was 0.08 moles, which lines up perfectly with Nitro Benzoic Acid. Then we calculated that B2s molecular weight was 0.06, which ended up being Malic Acid. Also, C1 was determined as Formic Acid because the Molecular Weight was 0.379. If there is any misunderstanding about these values, feel free to take a peek at my calculations page. This lab experiment was quite a difficult one. First of all, the most important point of the report is proper instruction. Then, the next thing that is a necessity is proper communication between lab partners. Had everyone understood everything along with everyone else, there would have been no problem with anything. With the calculations, we also determined what the Ka values were equal to. For the Nitro Benzoic Acid, the Ka value was equal to 3.1E-4. This was also true for the Malic Acid as well. For the Formic Acid, however, the Ka value came to be 2.51E-4, which is a bit smaller than the first two acids.