HIn < === > H+ + In- The following absorbance data were obtained for a 5.00 x 10

Question

HIn < === > H+ + In- The following absorbance data were obtained for a 5.00 x 10-4 M solution of HIn in 0.1 M NaOH and 0.1 HCl. Measurements were made at a wavelength of 485 nm and 625 nm with 1.00 cm cell.
0.1 M NaOH A(485 nm)=0.052, A(625 nm)=0.823
0.1 M HCl A(485 nm)=0.454, A(625 nm)=0.176
In the NaOH solution, essentially all of the indicator is present as In-; in the acidic solution, it is essentially
all in the form of HIn.
Calculate the acid dissociation constant for the indicator if a pH 5.00 buffer containing a small amount
of the indicator exhibits an absorbance of 0.472 at 485 nm and 0.351 at 625 nm (1.00 cm cells) What is the pH of a solution containing a small amount of the indicator that exhibits an absorbance of
0.530 at 485 nm and 0.216 at 625 nm (1.00 cm cells).

please solve step-by-step and explain (as you noticed i couldn't break the question because i need the first question for the second one. i know the rules and it wasn't my intention). i appreciate your time and help

Explanation / Answer

ph=6.5(approx)

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