A solution containing Mg2+ was buffered to pH 9.97 and titrated with EDTA. Eriochrome black T, with pKa1 = 6.3 and pKa2 = 11.6 was used as the indicator. It %3D is a diprotic acid, H2E What is the fraction of the predominant form of eriochrome black T in solution at this pH? (To answer this, report the alpha fraction of the indicator's most prevalent species at this pH) Review text sections 10.4 and 10.5 for help with this!

A solution containing Mg2+ was buffered to pH 9.97 and titrated with EDTA. Eriochrome black T, with pKa1 = 6.3 and pKa2 = 11.6 was used as the indicator. It %3D is a diprotic acid, H2E What is the fraction of the predominant form of eriochrome black T in solution at this pH? (To answer this, report the alpha fraction of the indicator's most prevalent species at this pH) Review text sections 10.4 and 10.5 for help with this!

Chemistry: Principles and Practice

3rd Edition

ISBN:9780534420123

Author:Daniel L. Reger, Scott R. Goode, David W. Ball, Edward Mercer

Publisher:Daniel L. Reger, Scott R. Goode, David W. Ball, Edward Mercer

Chapter16: Reactions Between Acids And Bases

Section: Chapter Questions

Problem 16.84QE: Phenolphthalein is a commonly used indicator that is colorless in the acidic form (pH 8.3) and pink...

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Phenolphthalein is a commonly used indicator that is colorless in the acidic form (pH 8.3) and pink in the base form (pH 10.0). It is a weak acid with a pKa of 8.7. What fraction is in the acid form when the acid color is apparent? What fraction is in the base form when the base color is apparent?
Malonic acid (HO2CCH2CO2H) is a diprotic acid. In the titration of malonic acid w ith NaOH, stoichiometric points occur at pH = 3.9 and 8.8. A 25.00-mL sample of malonic acid of unknown concentration is titrated with 0.0984 M NaOH, requiring 31.50 mL of the NaOH solution to reach the phenolphthalein end point. Calculate the concentration of the initial malonic acid solution. (Sec Exercise 113.)
Sketch two pH curves, one for the titration of a weak acid with a strong base and one for a strong acid with a strong base. How are they similar? How are they different? Account for the similarities and the differences.
Given three acid-base indicatorsâ€”methyl orange (end point at pH 4), bromthymol blue (end point at pH 7), and phenolphthalein (end point at pH 9)â€”which would you select for the following acid-base titrations? (a) perchloric acid with an aqueous solution of ammonia (b) nitrous acid with lithium hydroxide (c) hydrobromic acid with strontium hydroxide (d) sodium fluoride with nitric acid
Consider the following two acids: pKa1 = 2.98; pKa2 = 13.40 HO2CCH2CH2CH2CH2CO2H Adipic acid pKa1 = 4.41; pKa2 = 5.28 In two separate experiments the pH was measured during the titration of 5.00 mmol of each acid with 0.200 M NaOH. Each experiment showed only one stoichiometric point when the data were plotted. In one experiment the stoichiometric point was at 25.00 mL added NaOH, and in the other experiment the stoichiometric point was at 50.00 mL NaOH. Explain these results.
Fifty cm3 of 1.000 M nitrous acid is titrated with 0.850 M NaOH. What is the pH of the solution (a) before any NaOH is added? (b) at half-neutralization? (c) at the equivalence point? (d) when 0.10 mL less than the volume of NaOH to reach the equivalence point is added? (e) when 0.10 mL more than the volume of NaOH to reach the equivalence point is added? (f) Use your data to construct a plot similar to that shown in Figure 14.10 (pH versus volume NaOH added).
In the titration of 50.00 mL 0.0200M weak base B using 0.0150 M HCI, which indicator is the best one to be used? (pK, of the weak base B is 10.50). Indicator 2: Methyl red: pH transition = 4.8-6.0 Indicator 1: Cresol purple: pH transition = 1.2-2.8 Indicator 4: Thymolthalein: pH transition = 8.5-10.5 O Indicator 5: Indigo Carmine: pH transition= 11.6- 14.0 O Indicator 3: Cresol red: pH transition = 7.2-8.8
You are asked to prepare a 200.0 mL buffer solution of pH 8.52 from the following hypohalous acids: Hypobromous acid, HBro Hypochlorous acid, HCIO Hypoiodous acid, HIO (Ka = 2.0 x 10) (K, = 3.0 x 10) (Ka = 2.0 x 10-11) The available reagents are 5.0 M each of the acids and solids NaCIO (74.44 g/mol), NaBro (118.9 g/mol) and Nalo (165.9 g/mol). a. What would be the concentration of the salt if the required concentration of the acid component is 1.00 M? b. How much of the acid will you use? c. How much of the salt is needed?
Salts containing the phosphate ion are added to municipalwater supplies to prevent the corrosion of lead pipes. (a) Basedon the pKa values for phosphoric acid (pKa1 = 7.5 x 10 - 3,pKa2 = 6.2 x 10 - 8, pKa3 = 4.2 x 10 - 13) what is the Kbvalue for the PO43 - ion? (b) What is the pH of a 1 x 10 -3 M solution of Na3PO4 (you can ignore the formation ofH2PO4- and H3PO4)?
In the titration of 50.00 mL 0.0200M weak base B using 0.0150 M HCI, which indicator is the best one to be used? (pK, of the weak base B is 10.50). Indicator 4: Thymolthalein: pH transition = 8.5-10.5 OIndicator 5: Indigo Carmine: pH transition= 11.6- 14.0 Indicator 3: Cresol red: pH transition 7.2-8.8 Indicator 1: Cresol purple: pH transition = 1.2-2.8 Indicator 2: Methyl red: pH transition = 4.8-6.0
A certain indicator, HA, has a Ka value of 6.3 x 10-7. The protonated form of the indicator is yellow and the ionized form is red. What is the pKa of the indicator? pK₂ = What is the color of this indicator in a solution with pH = 4? yellow red orange
Calculate the pH at the equivalence point in titrating 0.069 M solutions of each of the following with 0.098 M NaOH. (a) periodic acid (HIO4) pH = (b) benzoic acid (HC>HSO2), Ka = 6.3e-05 pH = (c) hydrazoic acid (HN3), Ka - 1.9e-05 pH = O4 Suhmiecinne IIsed