Titration Of An Unknown Solution

The results in Table 1 show which of the unknown solutions were bases and which ones were acids. There are many different definitions of acids and bases, such as the Bronsted-Lowry, the Arrhenius, and Lewis definitions. According to The Editors of Encyclopædia Britannica5, a Bronsted-Lowry acid is, “any compound that can transfer a proton to any other compound,” and a base is, “the compound that accepts the proton”. As stated by Librerexts3, “Arrhenius acids form hydrogen ions in aqueous solutions with Arrhenius bases forming hydroxide ions”. The third definition of an acid/base is the Lewis definition. As reported by Acids and Bases1, “A Lewis acid is an electron-pair acceptor ... a Lewis base, therefore, is an electron-pair donor”. In the

The reason titrations are useful is because they offer an easy and reliable method of determining molarity if the concentration is unknown. The titrant would also have to be the opposite of the unknown, so an acid would be titrated with a base and vice versa. This is because the goal of a titration is to determine the amount of titrant needed (in milliliters) to bring the pH of an unknown solution to 7. The number of milliliters of titrant used, the milliliters of unknown used, and the molarity of the known solution would then be used to calculate the molarity of the unknown solution. Out of the three unknowns, unknown 5 had the greatest molarity with a concentration of 1.104 mols/liter, and required the greatest number of milliliters to reach a pH of 7, at 5.52mL. Unknown 4 had the second highest molarity with a concentration of 1.072 mols/liter, and required the second highest number of milliliters to reach a pH of 7 at 5.36mL. Unknown 2 had the lowest concentration with a molarity of 0.9016 mols/liter, and required the smallest number of milliliters of titrant to reach a pH of 7 at only

In this experiment, each of the unknown solutions were tested for the presence of chloride, nitrate, and acetate. For unknown 2, there was no precipitate formed during the chloride test, concluding that it did not contain chloride. Unknown 2 also produced a negative for the nitrate test, since a brown ring did not form, indicating that it did not contain any nitrate ions. The last test, the acetate test, was not conducted on unknown 2 due to the results from the cation tests. For unknown 4, the chloride test also produced a negative result, indicating the absence of any chloride ions. However, unknown 4 did produce a positive result for the nitrate test, indicating the solution contained nitrate. Since the nitrate test produced a positive, the acetate test was not conducted for unknown 4. Lastly, unknown 5 was tested using the chloride test, and again produced a negative result, meaning that the solution did not contain any chloride ions. Unknown 5 also produced a negative for the nitrate test. Since unknown 5 did not produce a positive result for either of the other two anion tests, the acetate test was conducted and a positive result was achieved. This indicated that unknown 5 had acetate, and since there was only one option for an acid with acetate ions, the identity of unknown 5 was