11.The pKa of a weak acid was determined by measuring the pH of a solution containing the weak acid at 0.40 M and its conjugate base at 0.60 M. The measured pH was 7.8. What is the pKa of the weak acid? a. 8.0 b. 7.8 c. 7.6 d. 7.0 e. 7.4

Which of the following is true about the titration curves of solutions of weak acids? A. The pH for optimal buffering power of a weak acid is 7.00. B. You can calculate the pKa of an acid, given the pH and the molar ratio of the acid and its conjugate base. C. The pKa of a weak acid is the pH at which the acid is completely dissociated. D. At a pH below the pKa of a weak acid, its conjugate base will predominate.

The pKa of a weak acid was determined by measuring the pH of a solution containing the weak acid at 0.30 M and its conjugate base at 0.30 M. The measured pH was 8.0. What is the pKa of the weak acid?

Acetic acid (pK, = 4.76) was dissolved in an aqueous solution buffered to a pH of 5.76. Determine the ratio of the concentrations of acetate ion and acetic acid in this solution. Which species predominates under these conditions? O The acid predominates, because the ratio of [acetate ion]/[acetic acid] = 0.01. O Neither species predominates, because the ratio of [acetate ion]/[acetic acid] = 1. O The conjugate base predominates, because the ratio of [acetate ion]/[acetic acid] = 10. The conjugate base predominates, because the ratio of [acetate ion]/[acetic acid] = 100. %3D O The acid predominates, because the ratio of [acetate ion]/[acetic acid] = 0.1.

A student obtains the following data from the Determining the pKa of an Acid-Base Indicator experiment. Using this data, calculate the pKa of the indicator in the fourth solution. Solution Abs. pH 3.4 + HCI 0.054 pH 4.6 + NaOH 0.564 Sample # actual pH Abs. 1 3.48 0.130 2345 3.77 0.217 3.99 0.296 4.37 0.388 4.54 0.468 Your Answer: Answer (2 points) After creating a graph of pH versus log([HIn]/[In-]), the following trendline is obtained. = -1.0291× + 3.721 y=-1 Calculate the pKa of bromophenol blue from this data to three decimal places. Your Answer: Answer MacBook Pro

Weak base titration: You are titrating a 31.25 mL solution of 0.100 M trimethylamine (pKb = 4.20) with 0.125 M HCI. Calculate the pH and plot along the titration curve after the addition of the volumes shown below. Make a plot of the titration curve. a. 0 mL titrant b. 10.0 mL c. 15.0 mL d. 20.0 mL e. 25.0 mL f. 30.0 mL

A chemist needs to buffer a particular solution between pH 3.50 and 4.00 at 25 °C. Consider the pKą values (all at 25 °C) and determine which solution is most appropriate for the task. HCIO pK₂ = 1.96 C6H5CO₂H pK₂ = 4.19 C5HẠNH* pK₂ = 5.25 HBrO pK₂ = 8.70 HCN pK₂ = 9.21 C6H5CO₂H and KC6H5CO2 C5H4NHCI and C5H4N HBrO and KBRO HCIO and NaCIO HCN and NaCN

4. The pKa of a particular weak acid is 4.81. What is the pH of the weak acid solution when exactly half of the acid is neutralized? pH =

Chemistry The theoretical pka of a weak acid is 3.54. Calculate the pKa experimental error of a solution composed of 10 mL of 0.23 M HA, 15 mL of 0.17 M of NaA and 20 mL of water. The measured pH of this solution is 3.17. Note: Report only the numerical answer of the percent without the % symbol.

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