postlab 6.docx - Introduction Titration is a process used...

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Introduction Titration is a process used in analytical chemistry labs to determine the concentration of an unknown substance by using a solution with a known concentration and amount. In this experiment, the purpose was to determine the amount of Ascorbic acid in a non-chewable Vitamin C tablet. Vitamin C is an antioxidant needed by the human body. Ascorbic acid can be oxidized by Bromine, which allows us to calculate the concentration. By performing titration with KBr O 3 and adding Potassium Bromide to an acidified solution, the products result in a known amount of Bromine. The Bromine ion products react with all the ascorbic acid immediately after being produced. The titration in this experiment requires a two-step titration also known as a back-titration. In the first step, a faint yellow will appear when there is excess Bromine in the solution. The second step of titration is the back titration part of the experiment. In this step, the reaction of Bromine and Iodide takes place because the iodine reacts with the sodium thiosulfate solution to determine the number of moles of Ascorbic acid. The type of reaction that is happening here is redox with oxidation and reduction. When the process of oxidation takes place a substance is losing electrons. The sister of oxidation is reduction and in this process the substance is gaining electrons. These two processes always work together in a reaction.

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