The acid-base indicator Hln undergoes the following reaction in dilute

Chapter 14, Problem 14-10

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The acid-base indicator Hln undergoes the following reaction in dilute aqueoussolution:The following absorbance data were ohtained for a 5.00 X IW' M solution ofHIn in 0.1 M NaOH and 0.1 M HCI. Measurements were made at wavelengths of485 nm and 625 nm with 1.00cm cells.0.1 MNaOH0.1 MHCIAm = 0.075A.S) = 0.487A62; = 0.904A62j = 0.181[n the NaOH solution, essentially all of the indicator is present as In ; in theacidic solution, it is essentiallv all in the form of HIn.(a) Calculate molar absorpti~ities for In - and HIn at 485 and 625 nm.(h) Calculate the acid dissociation constant for the indicator if a pH 5.00 buffercontaining a small amount of the indicator exhibits an absorbance of 0.567 at.+85nm and 0.395 at 625 nm (1.00-cm cells).(c) What is the pH of a solution containing a small amount of the indicator thatexhihits an absorbance of 0.492 at 485 nm and 0.2'+5 at 635 nm (l.OO-cmcells)'!(d) A 25.00-mL aliquot of a solution of purified weak organic acid HX requiredexactly 2.+.20mL of a standard solution of a strong hase to reach a phenolphthaleinend point. When exactly 12.10 mL of the hase was added to a second 25.00-mL aliquot of the acid, which contained a small amount of the indicatorunder consideration, the absorbance was found to be 0.333 at 485 nmand 0.655 at 625 nm (I.OO-cmcells). Calculate the pH of the solution and K,for the weak acid.(e) What would be the absorhance o[ a solution at 485 and 625 nm (1.50-cmcells) that was 2.00 x 10-' M in the indicator and was buffered to a pH of6.000"