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.

Homework Answers

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
A 0.26 M solution of compound "B" is measured in a 1.00 cm path length cuvette...
A 0.26 M solution of compound "B" is measured in a 1.00 cm path length cuvette at a wavelength of 565 nm. The percentage of light transmitted through the cell is 44%. What is the molar absorbance of this sample at 565 nm (in units of mol-1 cm-1)?
An unknown amount of a compound with a molecular mass of 259.61 g/mol is dissolved in...
An unknown amount of a compound with a molecular mass of 259.61 g/mol is dissolved in a 10-mL volumetric flask. A 1.00-mL aliquot of this solution is transferred to a 25-mL volumetric flask and enough water is added to dilute to the mark. The absorbance of this diluted solution at 347 nm is 0.525 in a 1.000-cm cuvette. The molar absorptivity for this compound at 347 nm is ε347 = 6557 M–1 cm–1. (a) What is the concentration of the...
The standard solution of 2.50 × 10-5 M of Red-40 dye (molar mass = 496.42 g.mol-1)...
The standard solution of 2.50 × 10-5 M of Red-40 dye (molar mass = 496.42 g.mol-1) has an absorbance of 0.467 at 510 nm using 1.00 cm cuvette. Determine the mass percentage of Red-40 dye in a Kool-Aid packet if a solution of an aliquot (0.1245 g) of Kool-Aid powder dissolved in 1 L of water has an absorbance of 0.248 at 510 nm
A student prepared the following two mixtures and recorded their absorbances in a cuvette with a...
A student prepared the following two mixtures and recorded their absorbances in a cuvette with a 1.00 cm path length: Mix # .20 M Fe3 .020 M Fe3 3.25*10^-4M SCN Absorbance 1 10.0 mL -- 10.0 mL .708 2 -- 10.0 mL 10.0 mL .423 1. Write the balanced equilibrium reaction of Fe3 (aq) with SCN (aq) to form [FeSCN]2 (aq). 2. Write the equilibrium formation constant equation for the reaction (Kf expression). Determination of moral absoptivity 3. Assuming that...
1.) An aqueous solution contains 0.23 M hydrofluoric acid. One Liter of this solution could be...
1.) An aqueous solution contains 0.23 M hydrofluoric acid. One Liter of this solution could be converted into a buffer by the addition of: (Assume that the volume remains constant as each substance is added.) 0.12 mol HClO4 0.23 mol KNO3 0.24 mol HClO4 0.24 mol KF 0.117 mol NaOH 2.) An aqueous solution contains 0.34 M ammonia. One liter of this solution could be converted into a buffer by the addition of: (Assume that the volume remains constant as...
The first-order decomposition of a colored chemical species, X, into colorless products is monitored with a...
The first-order decomposition of a colored chemical species, X, into colorless products is monitored with a spectrophotometer by measuring changes in absorbance over time. Species X has a molar absorptivity constant of 5.00x103 cm–1M–1 and the path length of the cuvette containing the reaction mixture is 1.00 cm. The data from the experiment are given in the table below. [X] (M) Absorbance (A) Time (min) ? 0.600 0.0 4.00 x 10-5 0.200 35.0 3.00 x 10-5 0.150 44.2 1.50 x...
1. A standard solution of 100 ppm (100 mg / L) of an organic compound was...
1. A standard solution of 100 ppm (100 mg / L) of an organic compound was analyzed and this has a maximum absorption band at 270 nm. A calibration curve was prepared from which the following data were obtained: Conc. (Ppm) 1 1,5 2 3 4 Absorbance 0.1282   0.1940 0.2615 0.3995 0.5422        If 2 ml of an unknown solution of this compound are diluted to 50 ml, an absorbance of 0.425 is obtained. a. Calculate the concentration...
1.) You will work with 0.10 M acetic acid and 17 M acetic acid in this...
1.) You will work with 0.10 M acetic acid and 17 M acetic acid in this experiment. What is the relationship between concentration and ionization? Explain the reason for this relationship 2.) Explain hydrolysis, i.e, what types of molecules undergo hydrolysis (be specific) and show equations for reactions of acid, base, and salt hydrolysis not used as examples in the introduction to this experiment 3.) In Part C: Hydrolysis of Salts, you will calibrate the pH probe prior to testing...
1. Given the following reaction     2C2H6(l)   +      7 O2(g)   ®           4CO2(g)      +     
1. Given the following reaction     2C2H6(l)   +      7 O2(g)   ®           4CO2(g)      +        6H2O(l) How many moles of water are produced when 4.5 moles of oxygen react?        (Hint: Use slides 5-8) 2. Given: I2     +    3 F2      ®     2 IF3 How many moles of I2 are needed to form 3 moles of IF3? How many moles of F2 are needed to form 10 moles of IF3? How many moles of I2 are needed to react with 3.5 moles of F2?        ...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT