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
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).