You are given 2 ml of a stock solution of phenol red at a concentration of 258 mg/ml and 20 ml of 0.5 potassium phosphate buffer pH 7. You need 100 ml of a solution containing 50 mM potassium phosphate buffer pH 7 and 87 ug/ml phenol red to do a spectrophotometric analysis. How would you make this new solution?

You are given 2 ml of a stock solution of phenol red at a concentration of 258 mg/ml and 20 ml of 0.5 potassium phosphate buffer pH 7. You need 100 ml of a solution containing 50 mM potassium phosphate buffer pH 7 and 87 ug/ml phenol red to do a spectrophotometric analysis. How would you make this new solution?

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter20: Applications Of Oxidation/reduction Titrations

Section: Chapter Questions

Problem 20.6QAP

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A NaOH solution is adjusted by titrating 0.8592 g of primary standard potassium acid phthalate to the phenolphthalein endpoint. Since 32.67 mL of base solution is required for this titration, what is the molarity of the base? (Potassium acid phthalate: 204 g / mol, NaOH: 40 g / mol)
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Part A: Standardization of a Sodium Hydroxide Solution Titration 1 Titration 2 Titration 3 Mass of 125 mL flask 45.849g 46.715g 44.953g Mass of flask and KHP 46.849g 47.745g 46.003g Initial buret reading (mL) 0.5 ml 0.5 ml 0.5 ml Final buret reading (mL) 27.8 ml 26.5 ml 26.7 ml Volume of NaOH used (mL) 45.11 ml 45.06 ml 45.14 ml Calculations Titration 1 Titration 2 Titration 3 Moles of KHP Moles of NaOH Molarity of NaOH Average Molarity of NaOH: _______________
The following graph shows the pH curve for the titration of 25 mL of a 0.1 M monoprotic acid solution with a 0.1 M solution of a monoprotic base. 14- pH 12 10 8 6 4 2 5 10 15 20 25 30 35 40 45 50 mL of 0.1 M base added (1) The pH curve represents the titration of a | acid with a |base. (2) Choose a suitable indicator for the endpoint of the titration from the following pulldown list. Malachite green 0.2 1.8 Thymol blue 1.2 2.8 8.0 9.6 Methyl orange 3.2 4.4 Bromocresol green 3.8 5.4 Methyl red 4.8 6.0 Bromothymol blue 6.0 7.6 Cresol red 7.0 8.8 Phenolphthalein 8.2 10.0 Thymolphthalein 94 10.6 Alizarin yellow 10.1 12.0 pH 0 1 2 4 7 8 10 11 12 13 14 6.
Topic: Acid-Base Titration What is a primary standard? What are the requirements to consider a substance a primary standard?