An aqueous solution contains 0.26 M ammonium iodide. 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.) (Select all that apply.) 0.25 mol NH3 0.26 mol HNO3 O 0.12 mol HNO3 0.25 mol NaI 0.06 mol Ca(OH)2

You are given the following acidbase titration data, where each point on the graph represents the pH after adding a given volume of titrant (the substance being added during the titration). a What substance is being titrated, a strong acid, strong base, weak acid, or weak base? b What is the pH at the equivalence point of the tiration? c What indicator might you use to perform this titration? Explain.

The three flasks shown below depict the titration of an aqueous NaOH solution with HCl at different points. One represents the titration prior to the equivalence point, another represents the titration at the equivalence point, and the other represents the titration past the equivalence point. (Sodium ions and solvent water molecules have been omitted for clarity.) a Write the balanced chemical equation for the titration. b Label each of the beakers shown to indicate which point in the titration they represent. c For each solution, indicate whether you expect it to be acidic, basic, or neutral.

Explain why even though an aqueous acetic acid solution contains acetic acid and acetate ions, it cannot be a buffer.

Each symbol in the box below represents a mole of a component in one liter of a buffer solution; represents the anion (X-), = the weak acid (HX), = H+, and =OH. Water molecules and the few H+ and OH- ions from the dissociation of HX and X- are not shown. The box contains 10 mol of a weak acid, , in a liter of solution. Show what happens upon (a) the addition of 2 mol of OH- (2 ). (b) the addition of 5 mol of OH- (5 ). (c) the addition of 10 mol of OH- (10 ). (d) the addition of 12 mol of OH- (12 ). Which addition (a)-(d) represents neutralization halfway to the equivalence point?

Two samples of 1.00 M HCl of equivalent volumes are prepared. One sample is titrated to the equivalence point with a 1.00 M solution of sodium hydroxide, while the other sample is titrated to the equivalence point with a 1.00 M solution of calcium hydroxide. a Compare the volumes of sodium hydroxide and calcium hydroxide required to reach the equivalence point for each titration. b Determine the pH of each solution halfway to the equivalence point. c Determine the pH of each solution at the equivalence point.

A buffer solution is prepared by adding 5.50 g of ammonium chloride and 0.0188 mol of ammonia to enough water to make 155 mL of solution. (a) What is the pH of the buffer? (b) If enough water is added to double the volume, what is the pH of the solution?

Sulfanilic acid (NH2C6H4SO3H) is used in manufacturing dyes. It ionizes in water according to the equilibrium equation NH2C6H4SO3H(aq)+H2O(l)NH2C6H4SO3(aq)+H3O+(aq)Ka=5.9104 A buffer is prepared by dissolving 0.20 mol of sulfanilicacid and 0.13 mol of sodium sulfanilate (NaNH2C6H4SO3) in water and diluting to 1.00 L. Compute the pH of the solution. Suppose 0.040 mol of HCl is added to the buffer.Calculate the pH of the solution that results.

Sketch the titration curve for a weak acid titrated by a strong base. When performing calculations concerning weak acidstrong base titrations, the general two-slep procedure is to solve a stoichiometry problem first, then to solve an equilibrium problem to determine the pH. What reaction takes place in the stoichiometry part of the problem? What is assumed about this reaction? At the various points in your titration curve, list the major species present after the strong base (NaOH, for example) reacts to completion with the weak acid, HA. What equilibrium problem would you solve at the various points in your titration curve to calculate the pH? Why is pH 7.0 at the equivalence point of a weak acid-strong base titration? Does the pH at the halfway point to equivalence have to be less than 7.0? What does the pH at the halfway point equal? Compare and contrast the titration curves for a strong acidstrong base titration and a weak acidstrong base titration.

Calculate the pH of these buffers.