Compute the molar absorptivities

Reference no: EM13167474

An 8.0*10^-5M solution of an indicator, HIn was found to yield the following absorption data when 25 ml of the indicator solution was added to a 50.00 ml volumetric flask and diluted as indicated: (A 1.00 cm path length cell was used)

A. Diluted to 50.00 ml with 1M NaOH; A (subscript454)=0.207; A subscript 654=1.166

B. Diluted to 50.00 ml with 1M HCl; A subscript 454=0.888; a subscript 654= 0.356

C Diluted to 50.00 ml with a buffer of pH= 5.755; A subscript 454=0.400; A subscript 654=0.750

1. Calculate the molar absorptivities for HIn at 454 and 654nm

2. Calculate the molar absorptivities for In- at 454 and 654nm

3. set up two simultaneous equations, and determine the molar concentrations of HIn and In- in the buffer solutions

4. calculate the log ([In-]/[HIn]) for the buffer solution

5. calculate the pKa of the indicator

Reference no: EM13167474

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