1. What is the concentration of the vitamin C standard solution? Using a balance
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Question
1. What is the concentration of the vitamin C standard solution? Using a balance, 125mg of Vitamin C was weighed out and was added to a 100-mL beaker and dissolved in 50mL of DI water. This solution was poured into a 100-mL volumetric flask. The beaker was rinsed with two separate portions of 10mL of DI water and both risings were added to the volumetric flask as well. The volumetric flask was filled exactly to the line with additional DI water, the flask was stoppered and shaken well to ensure thorough mixing. Using a 5-mL volumetric pipet, 5 mL of the above solution was transferred to clean 100-mL volumetric flask and filled to the line with DI water. The solution was mixed thoroughly and kept stoppered when not in use.Explanation / Answer
125 mg vitamin c = 0.125/176.12 =0.000709 moles vol = 50 ml M = (0.000709 x1000/50) = 0.0142 2 portions of 10 ml of water added i.e 20 ml water added , so volume of water = 70 ml M = (0.000709 x1000/70) = 0.01013 M volume of flask is filled to line i.e upto 100ml it is filled with water M = (0.000709x1000/100) = 0.00709 5 ml of this solution contains = 0.00709 x5/1000 = 0.00003545 moles volume filled in flask = 100 ml level new molarity = (0.00003545 x1000/100) = 0.0003545 M is concentration of vitamin C final solution.
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