The Effect of Ph on a Food Preservative Essay

698 WordsOct 1, 20123 Pages
The Effect of pH on a Food Preservative September 18, 2012 Objective: To study the affect of pH on a food preservative. Chemical Equation: C6H5COONa + HCL ------ C6H5COOH + NaCl Procedure: This experiment was started with a clear solution of sodium benzoate and HCl was added to it, ultimately producing benzoic acid. First, .3395 g of sodium benzoate was weighed, then it was dissolved in water, causing it to disassociate into ions. Next, 3M of HCl were added drop wise to the solution until it reached a pH of 2, thus introducing the hydronium ion. This addition caused a white, solid benzoic acid to precipitate out of the solution. A vacuum filtration system was used to separate the solid from the liquid. What was once…show more content…
Once, the precipitate was ready to be placed in the oven there was not enough time to allow for it to dry for 10 minutes. The precipitate was only in the oven for about 5 minutes, therefore, when weighed there was excess liquid in the precipitate. The final weight of the precipitate was .45 g which was more than the amount that was started with. From this end weight, it can be deduced that there was excess liquid in the end result. Post-Lab: 1. The experiment began with a clear solution of sodium benzoate, once 3 M of HCl were added to achieve a pH of 2, the clear solution became a precipitate. Sodium benzoate was water soluble, but the yield of benzoic acid became quite insoluble in water. 3b. Although, a low amount of HCl was used, the waste can still cause health risks and risks to the environment because it was not just one person doing the experiment, therefore increasing the waste of HCl. Water was also used to wash the vial to remove all solids that might be sticking to the side of the vial, therefore, wasting water, which is not green. 4. If you start adding NaOH to the solution in small amounts, NaOH neutralizes part of the HCl, (moles of HCl to moles of NaOH) so the pH begins to increase slowly, this raises the soluability. This allows for the equivalent point to be reached: moles of HCl = moles of NaOH. By continuing to add the NaOH, pH will
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