Question
An acid-base indicator, HIn, dissociates according to the following reaction in an aqueous solution. HIn---> In-...
An acid-base indicator, HIn, dissociates according to the following reaction in an aqueous solution. HIn---> In- + H+ . The protonated form of the indicator, HIn, has a molar absorptivity of 3827 M–1·cm–1 and the deprotonated form, In–, has a molar absorptivity of 26210 M–1·cm–1 at 440 nm. The pH of a solution containing a mixture of HIn and In– is adjusted to 5.92. The total concentration of HIn and In– is 0.000117 M. The absorbance of this solution was measured at 440 nm in a 1.00 cm cuvette and was determined to be 0.851. Calculate pKa for HIn.
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