a. What was the concentration of the NaOH? Concentration = м b. What is the pH at the equivalence point? рн - c. Which indicator, bromothymol blue, phenolpl

Define a buffer solution. What makes up a buffer solution? How do buffers absorb added H+ or OH with little pH change? Is it necessary that the concentrations of the weak acid and the weak base in a buffered solution be equal? Explain. What is the pH of a buffer when the weak acid and conjugate base concentrations are equal? A buffer generally contains a weak acid and its weak conjugate base, or a weak base and its weak conjugate acid, in water. You can solve for the pH by setting up the equilibrium problem using the K.a reaction of the weak acid or the Kb reaction of the conjugate base. Both reactions give the same answer for the pH of the solution. Explain. A third method that can be used to solve for the pH of a buffet solution is the HendersonHasselbalch equation. What is the HendersonHasselbalch equation? What assumptions are made when using this equation?

Consider the nanoscale-level representations for Question 111 of the titration of the aqueous strong acid HA with aqueous NaOH, the titrant. Water molecules and Na+ ions are omitted for clarity. Which diagram corresponds to the situation: (a) After a very small volume of titrant has been added to the initial HA solution? (b) Halfway to the equivalence point? (c) When enough titrant has been added to take the solution just past the equivalence point? (d) At the equivalence point? Nanoscale representations for Question 111.

The weak base ethanolamine. HOCH2CH2NH2, can be titrated with HCl. HOCH2CH2NH2(aq)+H3O+(aq)HOCH2CH2NH3+(aq)+H2O(l) Assume you have 25.0 mL of a 0.010 M solution of ethanolamine and titrate it with 0.0095 M HCl. (Kb for ethanolamine is 3.2 107.) (a) What is the pH of the ethanolamine solution before the titration begins? (b) What is the pH at the equivalence point? (c) What is the pH at the halfway point of the titration? (d) Which indicator in Figure 17.11 would be the best choice to detect the equivalence point? (e) Calculate the pH of the solution after adding 5.00, 10.0, 20.0, and 30.0 mL of the acid. (f) Combine the information in parts (a), (b), (c), and (e), and plot an approximate titration curve.