(Solved): Bromothymol blue (BTB) is a pH indicator with exhibiting different colors depending on its protonati ...

Bromothymol blue (BTB) is a pH indicator with exhibiting different colors depending on its protonation
level at different pH. The following table is the absorption of 0.2% (w/v) BTB solution at 620 nm that corresponds
to the maximum absorption peak of deprotonated form of BTB. Mw of BTB is 624.38 g·mol?1. At pH 8, calculate
the molar concentrations of BTB and deprotonated BTB. You need to first find pKa of BTB.

5. (40 pts) Bromothymol blue (BTB) is a pH indicator with exhibiting different colors depending on its protonation level at different pH. The following table is the absorption of 0.2% (w/v) BTB solution at 620 nm that corresponds to the maximum absorption peak of deprotonated form of BTB. Mw of BTB is 624.38 g-mol-¹. At pH 8, calculate the molar concentrations of BTB and deprotonated BTB. You need to first find pKa of BTB. 3 4 9 pH A(620 nm) 5 6 0.2 0.5 7 8 2.0 3.5 10 11 4 0 0 3.7 4