12. A buffer solution is prepared by adding 0.37 moles of NH4CI and 0.29 moles of NH3 to enough water to form 1.0 L of solution. Kb for NH3 is 1.8 × 105. NH3(aq) + H2O(aq) <=====> NH4+ (aq) + OH(aq) a. Calculate the pH of the buffer solution. b. Calculate the pH of the solution if 0.020 mol of NaOH is added (neglect volume changes).

Calculate the pH of a solution prepared by mixing 49.0 mL of butyric acid, HC4H7O2, with 6.15 g of KOH in water. The following data about butyric acid may be helpful: density=0.9595g/mL;K a =1.54105

A friend asks the following: Consider a buffered solution made up of the weak acid HA and its salt NaA. If a strong base like NaOH is added, the HA reacts with the OH to form A. Thus the amount of acid (HA) is decreased, and the amount of base (A) is increased. Analogously, adding HCI to the buffered solution forms more of the acid (HA) by reacting with the base (A). Thus how can we claim that a buffered solution resists changes in the pH of the solution? How would you explain buffering to this friend?

A solution with a pH of 9.22 is prepared by adding water to 0.413 mol of KX to make 2.00 L of solution. What is the pH of the solution after 0.368 mol of HX is added?

. Which component of a buffered solution is capable of combining with an added strong acid? Using your example from Exercise 60, show how this component would react with added HC1.

A solution consisting of 25.00 g NH4Cl in 178 mL of water is titrated with 0.114 M KOH. (a) How many milliliters of KOH are required to reach the equivalence point? (b) Calculate [Cl-], [K+], [NH3], and [OH-] at the equivalence point. (Assume that volumes are additive.) (c) What is the pH at the equivalence point?

A quantity of 0.15 M hydrochloric acid is added to a solution containing 0.10 mol of sodium acetate. Some of the sodium acetate is converted to acetic acid, resulting in a final volume of 650 mL of solution. The pH of the final solution is 4.56. a What is the molar concentration of the acetic acid? b How many milliliters of hydrochloric acid were added to the original solution? c What was the original concentration of the sodium acetate?

An aqueous solution contains a mixture of 0.0500 M HCOOH (Ka = 1.77 104) and 0.150 M CH3CH2COOH (Ka = 1.34 105). Calculate the pH of this solution. Because both acids are of comparable strength, the H+ contribution from both acids must be considered.

The pH of 1.0 108 M hydrochloric acid is not 8.00. The correct pH can be calculated by considering the relationship between the molarities of the three principal ions in the solution (H+, Cl, and OH). These molarities can be calculated from algebraic equations that can be derived from the considerations given below. a. The solution is electrically neutral. b. The hydrochloric acid can be assumed to be 100% ionized. c. The product of the molarities of the hydronium ions and the hydroxide ions must equal Kw. Calculate the pH of a 1.0 108-M HCl solution.

Calculate the pH of a buffer solution prepared from 0.155 mol of phosphoric acid, 0.250 mole of KH2PO4, and enough water to make 0.500 L of solution.