Acidic Analysis of common Soda
Your objective is to determine the concentration and pH of a common soda.
Background Information:
In a previous lab you titrated a strong acid against a strong base. At this point the salt and water produced were neutral and therefore the equivalence point is neutral. Typical soda is composed of a few different types of acids. These acids are weak and therefore the conjugates are weak bases. The equivalence point will not be neutral. However, when graphing, you will be able to see the equivalence point by a drastic change of ph. This usually swings through the neutral points. The acid turns into a base.
Pre-lab activity
Do an internet search:
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What types of acids are used in soda?
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What is the purpose of the acid in the soda?
Procedure:
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Set up pH meter.
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Collect sample of soda (_______mL)
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Put NaOH in buret (_______M). Fill it to the top. This will allow the pH meter to line up with the quantity the buret.
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Add 1mL at a time collecting pH from meter. Hit “KEEP” button.
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Print graph and datatable.
Data Analysis
1. With printed graph draw a vertical line at the equivalence point.
2. Determine quantity of moles in your sample.
3. Determine the molarity of your soda?
4. Determine the type of soda, from the label.
5. Is your acid polyprotic or monoprotic?
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