Quinine (C20H24N2O2) is the most important alkaloid

Consider two beakers of pure water at different temperatures. How do their pH values compare? Which is more acidic? more basic? Explain.

Differentiate between the terms strength and concentration as they apply to acids and bases. When is HCl strong? Weak? Concentrated? Dilute? Answer the same questions for ammonia. Is the conjugate base of a weak acid a strong base?

Sketch two graphs: (a) percent dissociation for weak acid HA versus the initial concentration of HA ([HA]0) and (b) H concentration versus [HA]0. Explain both.

Consider a solution prepared by mixing a weak acid HA and HCl. What are the major species? Explain what is occurring in solution. How would you calculate the pH? What if you added NaA to this solution? Then added NaOH?

Explain why salts can be acidic, basic, or neutral, and show examples. Do this without specific numbers

Consider two separate aqueous solutions: one of a weak acid HA and one of HCl. Assuming you started with 10 molecules of each: a. Draw a picture of what each solution looks like at equilibrium. b. What are the major species in each beaker? c. From your pictures, calculate the Ka values of each acid. d. Order the following from the strongest to the weakest base: H2O, A, Cl. Explain your order.

You are asked to calculate the H concentration in a solution of NaOH(aq). Because sodium hydroxide is a base, can we say there is no H, since having H would imply that the solution is acidic? 8

Consider a solution prepared by mixing a weak acid HA, HCl, and NaA. Which of the following statements best describes what happens? a. The H from the HCl reacts completely with the A from the NaA. Then the HA dissociates somewhat. b. The H from the HCl reacts somewhat with the A from the NaA to make HA, while the HA is dissociating. Eventually you have equal amounts of everything. c. The H from the HCl reacts somewhat with the A from the NaA to make HA while the HA is dissociating. Eventually all the reactions have equal rates. d. T d. The H from the HCl reacts completely with the A from the NaA. Then the HA dissociates somewhat until too much H and A are formed, so the H and A react to form HA, and so on. Eventually equilibrium is reached. Justify your choice, and for choices you did not pick, explain what is wrong with them.

Consider a solution formed by mixing 100.0 mL of 0.10 M HA (Ka  1.0  106 ), 100.00 mL of 0.10 M NaA, and 100.0 mL of 0.10 M HCl. In calculating the pH for the final solution, you would make some assumptions about the order in which various reactions occur to simplify the calculations. State these assumptions. Does it matter whether the reactions actually occur in the assumed order? Explain.

A certain sodium compound is dissolved in water to liberate Na ions and a certain negative ion. What evidence would you look for to determine whether the anion is behaving as an acid or a base? How could you tell whether the anion is a strong base? Explain how the anion could behave simultaneously as an acid and a base.

Acids and bases can be thought of as chemical opposites (acids are proton donors, and bases are proton acceptors). Therefore, one might think that Ka  1Kb. Why isnt this the case? What is the relationship between Ka and Kb? Prove it with a derivation.

Consider two solutions of the salts NaX(aq) and NaY(aq) at equal concentrations. What would you need to know to determine which solution has the higher pH? Explain how you would decide (perhaps even provide a sample calculation).

What is meant by pH? True or false: A strong acid solution always has a lower pH than a weak acid solution. Explain.

Why is the pH of water at 25C equal to 7.00?

Can the pH of a solution be negative? Explain.

Is the conjugate base of a weak acid a strong base? Explain. Explain why Cl does not affect the pH of an aqueous solution.

Match the following pH values: 1, 2, 5, 6, 6.5, 8, 11, 11, and 13, with the following chemicals (of equal concentration): HBr, NaOH, NaF, NaCN, NH4F, CH3NH3F, HF, HCN, and NH3. Answer this question without performing calculations.

The salt BX, when dissolved in water, produces an acidic solution. Which of the following could be true? (There may be more than one correct answer.) a. The acid HX is a weak acid. b. The acid HX is a strong acid. c. The cation B is a weak acid. Explain.

Anions containing hydrogen (for example, HCO3 and H2PO4 ) usually show amphoteric behavior. Write equations illustrating the amphoterism of these two anions.

Which of the following conditions indicate an acidic solution at 25C? a. pH  3.04 b. [H] 1.0  107 M c. pOH  4.51 d. [OH]  3.21  1012 M 21

Which of the following conditions indicate a basic solution at 25C? a. pOH  11.21 b. pH  9.42 c. [OH] [H] d. [OH] 1.0  107 M 22

Why is H3O the strongest acid and OH the strongest base that can exist in significant amounts in aqueous solutions?

How many significant figures are there in the following numbers: 10.78, 6.78, 0.78? If these were pH values, to how many significant figures can you express the [H]? Explain any discrepancies between your answers to the two questions.

In terms of orbitals and electron arrangements, what must be present for a molecule or an ion to act as a Lewis acid? What must be present for a molecule or an ion to act as a Lewis base?

Give three example solutions that fit each of the following descriptions. a. A strong electrolyte solution that is very acidic. b. A strong electrolyte solution that is slightly acidic. c. A strong electrolyte solution that is very basic. d. A strong electrolyte solution that is slightly basic. e. A strong electrolyte solution that is neutral.

Derive an expression for the relationship between pKa and pKb for a conjugate acidbase pair. (pK  log K.)

Consider the following statements. Write out an example reaction and K expression that is associated with each statement. a. The autoionization of water. b. An acid reacts with water to produce the conjugate base of the acid and the hydronium ion. c. A base reacts with water to produce the conjugate acid of the base and the hydroxide ion

Which of the following statements is(are) true? Correct the false statements. a. When a base is dissolved in water, the lowest possible pH of the solution is 7.0. b. When an acid is dissolved in water, the lowest possible pH is 0. c. A strong acid solution will have a lower pH than a weak acid solution. d. A 0.0010 M Ba(OH)2 solution has a pOH that is twice the pOH value of a 0.0010 M KOH solution.

Consider the following mathematical expressions. a. [H]  [HA]0 b. [H]  (Ka  [HA]0) 12 c. [OH]  2[B]0 d. [OH]  (Kb  [B]0) 12 For each expression, give three solutions where the mathematical expression would give a good approximation for the [H] or [OH]. [HA]0 and [B]0 represent initial concentrations of an acid or a base. 30.

Consider a 0.10 M H2CO3 solution and a 0.10 M H2SO4 solution. Without doing any detailed calculations, choose one of the following statements that best describes the [H] of each solution and explain your answer. a. The [H] is less than 0.10 M. b. The [H] is 0.10 M. c. The [H] is between 0.10 M and 0.20 M. d. The [H] is 0.20 M. 31

Of the hydrogen halides, only HF is a weak acid. Give a possible explanation

Explain why the following are done, both of which are related to acidbase chemistry. a. Power plants burning coal with high sulfur content use scrubbers to help eliminate sulfur emissions. b. A gardener mixes lime (CaO) into the soil of his garden.

Write balanced equations that describe the following reactions. a. the dissociation of perchloric acid in water b. the dissociation of propanoic acid (CH3CH2CO2H) in water c. the dissociation of ammonium ion in water

Write the dissociation reaction and the corresponding Ka equilibrium expression for each of the following acids in water. a. HCN b. HOC6H5 c. C6H5NH3

For each of the following aqueous reactions, identify the acid, the base, the conjugate base, and the conjugate acid.

For each of the following aqueous reactions, identify the acid, the base, the conjugate base, and the conjugate acid. a. b. c. HOCl C6H5NH2 OCl C6H5NH3 H2O HONH3 HONH2 H3O Al1H2O26 3 H2O H3O Al1H2O251OH2 2 HCO3 C5H

Classify each of the following as a strong acid or a weak acid.

Consider the following illustrations: Which beaker best illustrates what happens when the following acids are dissolved in water? a. HNO2 d. HF b. HNO3 e. HC2H3O2 c. HCl

Use Table 14.2 to order the following from the strongest to the weakest acid.

Use Table 14.2 to order the following from the strongest to the weakest base.

You may need Table 14.2 to answer the following questions. a. Which is the stronger acid, HCl or H2O? b. Which is the stronger acid, H2O or HNO2? c. Which is the stronger acid, HCN or HOC6H5?

You may need Table 14.2 to answer the following questions. a. Which is the stronger base, Cl or H2O? b. Which is the stronger base, H2O or NO2 ? c. Which is the stronger base, CNor OC6H5 ? Au

Calculate the [OH] of each of the following solutions at 25C. Identify each solution as neutral, acidic, or basic. a. [H]  1.0  107 M c. [H]  12 M b. [H]  8.3  1016 M d. [H]  5.4  105 M 44. Ca

Calculate the [H] of each of the following solutions at 25C. Identify each solution as neutral, acidic, or basic. a. [OH]  1.5 M b. [OH]  3.6  1015 M c. [OH]  1.0  107 M d. [OH]  7.3  104 M ClO2

Values of Kw as a function of temperature are as follows: Temperature (C) Kw 0 1.14  1015 25 1.00  1014 35 2.09  1014 40. 2.92  1014 50. 5.47  1014 a. Is the autoionization of water exothermic or endothermic? b. Calculate [H] and [OH] in a neutral solution at 50.C. 46. A

At 40.C the value of Kw is 2.92  1014. a. Calculate the [H] and [OH] in pure water at 40.C. b. What is the pH of pure water at 40.C? c. If the hydroxide ion concentration in a solution is 0.10 M, what is the pH at 40.C? 4

Calculate the pH and pOH of the solutions in Exercises 43 and 44.

Calculate [H] and [OH] for each solution at 25C. Identify each solution as neutral, acidic, or basic. a. pH  7.40 (the normal pH of blood) b. pH  15.3 c. pH  1.0 d. pH  3.20 e. pOH  5.0 f. pOH  9.60 4

Fill in the missing information in the following table. Acidic, Basic, pH pOH [H] [OH] or Neutral? Solution a 6.88 Solution b 8.4  1014 M Solution c 3.11 Solution d 1.0  107 M 50

Fill in the missing information in the following table. Acidic, Basic, pH pOH [H] [OH] or Neutral? Solution a 9.63 Solution b 3.9  106 M Solution c 0.027 M Solution d 12.2 5

The pH of a sample of gastric juice in a persons stomach is 2.1. Calculate the pOH, [H], and [OH] for this sample. Is gastric juice acidic or basic?

The pOH of a sample of baking soda dissolved in water is 5.74 at 25C. Calculate the pH, [H], and [OH] for this sample. Is the solution acidic or basic?

What are the major species present in 0.250 M solutions of each of the following acids? Calculate the pH of each of these solutions. a. HClO4 b. HNO3

A solution is prepared by adding 50.0 mL of 0.050 M HBr to 150.0 mL of 0.10 M HI. Calculate the concentrations of all species in this solution. HBr and HI are both considered strong acids.

Calculate the pH of each of the following solutions of a strong acid in water. a. 0.10 M HCl c. 1.0  1011 M HCl b. 5.0 M HCl

Calculate the pH of each of the following solutions containing a strong acid in water. a. 2.0  102 M HNO3 c. 6.2  1012 M HNO3 b. 4.0 M HNO3

Calculate the concentration of an aqueous HI solution that has pH  2.50. HI is a strong acid.

Calculate the concentration of an aqueous HBr solution that has pH  4.25. HBr is a strong acid.

How would you prepare 1600 mL of a pH  1.50 solution using concentrated (12 M) HCl?

A solution is prepared by adding 50.0 mL concentrated hydrochloric acid and 20.0 mL concentrated nitric acid to 300 mL water. More water is added until the final volume is 1.00 L. Calculate [H], [OH], and the pH for this solution. [Hint: Concentrated HCl is 38% HCl (by mass) and has a density of 1.19 g/mL; concentrated HNO3 is 70.% HNO3 (by mass) and has a density of 1.42 g/mL.]

What are the major species present in 0.250 M solutions of each of the following acids? Calculate the pH of each of these solutions. a. HNO2 b. CH3CO2H (HC2H3O2

What are the major species present in 0.250 M solutions of each of the following acids? Calculate the pH of each of these solutions. a. HOC6H5 b. HCN

Calculate the concentration of all species present and the pH of a 0.020 M HF solution.

Calculate the percent dissociation for a 0.22 M solution of chlorous acid (HClO2, Ka  1.2  102 ).

For propanoic acid (HC3H5O2, Ka  1.3  105 ), determine the concentration of all species present, the pH, and the percent dissociation of a 0.100 M solution.

A solution is prepared by dissolving 0.56 g benzoic acid (C6H5CO2H, Ka  6.4  105 ) in enough water to make 1.0 L of solution. Calculate [C6H5CO2H], [C6H5CO2 ], [H], [OH], and the pH of this solution. 67

Monochloroacetic acid, HC2H2ClO2, is a skin irritant that is used in chemical peels intended to remove the top layer of dead skin from the face and ultimately improve the complexion. The value of Ka for monochloroacetic acid is 1.35  103 . Calculate the pH of a 0.10 M solution of monochloroacetic acid.

Formic acid (HCO2H) is secreted by ants. Calculate [H] and the pH of a 0.025 M solution of formic acid (Ka  1.8  104 ).

Calculate the pH of a solution that contains 1.0 M HF and 1.0 M HOC6H5. Also calculate the concentration of OC6H5 in this solution at equilibrium.

A solution is made by adding 50.0 mL of 0.200 M acetic acid (Ka  1.8  105 ) to 50.0 mL of 1.00  103 M HCl. a. Calculate the pH of the solution. b. Calculate the acetate ion concentration.

Calculate the percent dissociation of the acid in each of the following solutions. a. 0.50 M acetic acid b. 0.050 M acetic acid c. 0.0050 M acetic acid d. Use Le Chteliers principle to explain why percent dissociation increases as the concentration of a weak acid decreases. e. Even though the percent dissociation increases from solutions a to c, the [H] decreases. Explain.

Using the Ka values in Table 14.2, calculate the percent dissociation in a 0.20 M solution of each of the following acids. a. nitric acid (HNO3) b. nitrous acid (HNO2) c. phenol (HOC6H5) d. How is percent dissociation of an acid related to the Ka value for the acid (assuming equal initial concentrations of acids)?

A 0.15 M solution of a weak acid is 3.0% dissociated. Calculate Ka.

An acid HX is 25% dissociated in water. If the equilibrium concentration of HX is 0.30 M, calculate the Ka value for HX.

The pH of a 1.00  102 M solution of cyanic acid (HOCN) is 2.77 at 25C. Calculate Ka for HOCN from this result.

The pH of a 0.063 M solution of hypobromous acid (HOBr but usually written HBrO) is 4.95. Calculate Ka.

A solution of formic acid (HCOOH, Ka  1.8  104 ) has a pH of 2.70. Calculate the initial concentration of formic acid in this solution.

A typical sample of vinegar has a pH of 3.0. Assuming that vinegar is only an aqueous solution of acetic acid (Ka  1.8  105 ), calculate the concentration of acetic acid in vinegar.

One mole of a weak acid HA was dissolved in 2.0 L of solution. After the system had come to equilibrium, the concentration of HA was found to be 0.45 M. Calculate Ka for HA.

You have 100.0 g saccharin, a sugar substitute, and you want to prepare a pH  5.75 solution. What volume of solution can be prepared? For saccharin, HC7H4NSO3, pKa  11.70 (pKa  log Ka).

Write the reaction and the corresponding Kb equilibrium expression for each of the following substances acting as bases in water. a. NH3 b. C5H5N

Write the reaction and the corresponding Kb equilibrium expression for each of the following substances acting as bases in water. a. aniline, C6H5NH2 b. dimethylamine, (CH3)2NH

Use Table 14.3 to help order the following bases from strongest to weakest.

Use Table 14.3 to help order the following acids from strongest to weakest.

Use Table 14.3 to help answer the following questions. a. Which is the stronger base, ClO4 or C6H5NH2? b. Which is the stronger base, H2O or C6H5NH2? c. Which is the stronger base, OHor C6H5NH2? d. Which is the stronger base, C6H5NH2 or CH3NH2?

Use Table 14.3 to help answer the following questions. a. Which is the stronger acid, HClO4 or C6H5NH3 ? b. Which is the stronger acid, H2O or C6H5NH3 ? c. Which is the stronger acid, C6H5NH3 or CH3NH3 ? 87

Calculate the pH of the following solutions. a. 0.10 M NaOH b. 1.0  1010 M NaOH c. 2.0 M NaOH

Calculate [OH], pOH, and pH for each of the following. a. 0.00040 M Ca(OH)2 b. a solution containing 25 g KOH per liter c. a solution containing 150.0 g NaOH per liter

What are the major species present in 0.015 M solutions of each of the following bases? a. KOH b. Ba(OH)2 What is [OH] and the pH of each of these solutions?

What are the major species present in the following mixtures of bases? a. 0.050 M NaOH and 0.050 M LiOH b. 0.0010 M Ca(OH)2 and 0.020 M RbOH What is [OH] and the pH of each of these solutions?

What mass of KOH is necessary to prepare 800.0 mL of a solution having a pH  11.56?

Calculate the concentration of an aqueous Sr(OH)2 that has pH  10.50.

What are the major species present in a 0.150 M NH3 solution? Calculate the [OH] and the pH of this solution.

For the reaction of hydrazine (N2H4) in water, H2NNH21aq2 H2O1l2 H2NNH3 1aq2 OH1aq2 HN Kb is 3.0  106 . Calculate the concentrations of all species and the pH of a 2.0 M solution of hydrazine in water.

Calculate [OH], [H], and the pH of 0.20 M solutions of each of the following amines. a. triethylamine [(C2H5)3N, Kb  4.0  104 ] b. hydroxylamine (HONH2, Kb  1.1  108 )

Calculate [OH], [H], and the pH of 0.40 M solutions of each of the following amines (the Kb values are found in Table 14.3). a. aniline b. methylamine

Calculate the pH of a 0.20 M C2H5NH2 solution (Kb  5.6  104 ).

Calculate the pH of a 0.050 M (C2H5)2NH solution (Kb  1.3  103 ).

What is the percent ionization in each of the following solutions? a. 0.10 M NH3 c. 0.10 M CH3NH2 b. 0.010 M NH3

Calculate the percentage of pyridine (C5H5N) that forms pyridinium ion, C5H5NH, in a 0.10 M aqueous solution of pyridine (Kb  1.7  109 ).

The pH of a 0.016 M aqueous solution of p-toluidine (CH3C6H4NH2) is 8.60. Calculate Kb.

Calculate the mass of HONH2 required to dissolve in enough water to make 250.0 mL of solution having a pH of 10.00 (Kb  1.1  108 ).

Write out the stepwise Ka reactions for the diprotic acid H2SO3.

Write out the stepwise Ka reactions for citric acid (H3C6H5O7), a triprotic acid.

Phosphoric acid is a common ingredient in traditional cola drinks. It is added to provide the drinks with a pleasantly tart taste. Although phosphoric acid is a triprotic acid, its protons are lost one at a time. Assuming that in cola drinks the concentration of phosphoric acid is 0.007 M, calculate the pH in this solution.

Arsenic acid (H3AsO4) is a triprotic acid with . Calculate [H], [OH], [H3AsO4], [H2AsO4 ], [HAsO4 2], and [AsO4 3] in a 0.20 M arsenic acid solution. 107

Calculate the pH and [S2] in a 0.10 M H2S solution. Assume

Calculate [CO3 2] in a 0.010 M solution of CO2 in water (usually written as H2CO3). If all the CO3 2 in this solution comes from the reaction what percentage of the H ions in the solution is a result of the dissociation of HCO3 ? When acid is added to a solution of sodium hydrogen carbonate (NaHCO3), vigorous bubbling occurs. How is this reaction related to the existence of carbonic acid (H2CO3) molecules in aqueous solution? 10

Calculate the pH of a 2.0 M H2SO4 solution.

Calculate the pH of a 5.0  103 M solution of H2SO4.

Arrange the following 0.10 M solutions in order of most acidic to most basic.

Arrange the following 0.10 M solutions in order from most acidic to most basic. See Appendix 5 for Ka and Kb values.

Given that the Ka value for acetic acid is 1.8  105 and the Ka value for hypochlorous acid is 3.5  108 , which is the stronger base, OCl or C2H3O2 ? 11

The Kb values for ammonia and methylamine are 1.8  105 and 4.4  104 , respectively. Which is the stronger acid, NH4 or CH3NH3 ? 11

Determine [OH], [H], and the pH of each of the following solutions. a. 1.0 M KCl b. 1.0 M KF

Calculate the concentrations of all species present in a 0.25 M solution of ethylammonium chloride (C2H5NH3Cl).

Calculate the pH of each of the following solutions. a. 0.10 M CH3NH3Cl b. 0.050 M NaCN

Calculate the pH of each of the following solutions. a. 0.12 M KNO2 c. 0.40 M NH4ClO4 b. 0.45 M NaOCl

An unknown salt is either NaCN, NaC2H3O2, NaF, NaCl, or NaOCl. When 0.100 mol of the salt is dissolved in 1.00 L of solution, the pH of the solution is 8.07. What is the identity of the salt?

Consider a solution of an unknown salt having the general formula BHCl, where B is one of the weak bases in Table 14.3. A 0.10 M solution of the unknown salt has a pH of 5.82. What is the actual formula of the salt

A 0.050 M solution of the salt NaB has a pH of 9.00. Calculate the pH of a 0.010 M solution of HB.

A 0.20 M sodium chlorobenzoate (NaC7H4ClO2) solution has a pH of 8.65. Calculate the pH of a 0.20 M chlorobenzoic acid (HC7H4ClO2) solution.

Calculate the pH of a 0.050 M Al(NO3)3 solution. The Ka value for Al(H2O)6 3 is 1.4  105

Calculate the pH of a 0.10 M CoCl3 solution. The Ka value for Co(H2O)6 3 is 1.0  105

Are solutions of the following salts acidic, basic, or neutral? For those that are not neutral, write balanced chemical equations for the reactions causing the solution to be acidic or basic. The relevant Ka and Kb values are found in Tables 14.2 and 14.3. a. NaNO3 c. C5H5NHClO4 e. KOCl b. NaNO2 d. NH4NO2 f. NH4OCl

Are solutions of the following salts acidic, basic, or neutral? For those that are not neutral, write balanced equations for the reactions causing the solution to be acidic or basic. The relevant Ka and Kb values are found in Tables 14.2 and 14.3. a. KCl c. CH3NH3Cl e. NH4F b. NH4C2H3O2 d. KF f. CH3NH3CN

Place the species in each of the following groups in order of increasing acid strength. Explain the order you chose for each group. a. HIO3, HBrO3 c. HOCl, HOI b. HNO2, HNO3 d. H3PO4, H3PO3

Place the species in each of the following groups in order of increasing base strength. Give your reasoning in each case. a. IO3 , BrO3 b. NO2 , NO3 c. OCl, OI 129

Place the species in each of the following groups in order of increasing acid strength. a. H2O, H2S, H2Se (bond energies: HOO, 467 kJ/mol; HOS, 363 kJ/mol; HOSe, 276 kJ/mol) b. CH3CO2H, FCH2CO2H, F2CHCO2H, F3CCO2H c. NH4 , HONH3 d. NH4 , PH4 (bond energies: NOH, 391 kJ/mol; POH, 322 kJ/mol) Give reasons for the orders you chose. 1

Using your results from Exercise 129, place the species in each of the following groups in order of increasing base strength. a. OH, SH, SeH b. NH3, PH3 c. NH3, HONH2 1

Will the following oxides give acidic, basic, or neutral solutions when dissolved in water? Write reactions to justify your answers. a. CaO b. SO2 c. Cl2O

Will the following oxides give acidic, basic, or neutral solutions when dissolved in water? Write reactions to justify your answers. a. Li2O b. CO2 c. SrO

Identify the Lewis acid and the Lewis base in each of the following reactions

Identify the Lewis acid and the Lewis base in each of the following reactions

Aluminum hydroxide is an amphoteric substance. It can act as either a BrnstedLowry base or a Lewis acid. Write a reaction showing Al(OH)3 acting as a base toward H and as an acid toward OH.

Zinc hydroxide is an amphoteric substance. Write equations that describe Zn(OH)2 acting as a BrnstedLowry base toward H and as a Lewis acid toward OH.

Would you expect Fe3 or Fe2 to be the stronger Lewis acid? Explain. H

Use the Lewis acidbase model to explain the following reaction.

A typical aspirin tablet contains 325 mg acetylsalicylic acid (HC9H7O4). Calculate the pH of a solution that is prepared by dissolving two aspirin tablets in one cup (237 mL) of solution. Assume the aspirin tablets are pure acetylsalicylic acid, Ka  3.3  104 .

Trichloroacetic acid (CCl3CO2H) is a corrosive acid that is used to precipitate proteins. The pH of a 0.050 M solution of trichloroacetic acid is the same as the pH of a 0.040 M HClO4 solution. Calculate Ka for trichloroacetic acid.

A typical vitamin C tablet (containing pure ascorbic acid, H2C6H6O6) weighs 500. mg. One vitamin C tablet is dissolved in enough water to make 200.0 mL of solution. Calculate the pH of this solution. Ascorbic acid is a diprotic acid.

Quinine (C20H24N2O2) is the most important alkaloid derived from cinchona bark. It is used as an antimalarial drug. For quinine, and (pKb  log Kb). Only 1 g quinine will dissolve in 1900.0 mL of solution. Calculate the pH of a saturated aqueous solution of quinine. Consider only the reaction described by pKb , where

Codeine (C18H21NO3) is a derivative of morphine that is used as an analgesic, narcotic, or antitussive. It was once commonly used in cough syrups but is now available only by prescription because of its addictive properties. If the pH of a 1.7  103 M solution of codeine is 9.59, calculate Kb.

A codeine-containing cough syrup lists codeine sulfate as a major ingredient instead of codeine. The Merck Index gives C36H44N2O10S as the formula for codeine sulfate. Describe the composition of codeine sulfate. (See Exercise 143.) Why is codeine sulfate used instead of codeine?

Sodium azide (NaN3) is sometimes added to water to kill bacteria. Calculate the concentration of all species in a 0.010 M solution of NaN3. The Ka value for hydrazoic acid (HN3) is 1.9  105 .

Papaverine hydrochloride (abbreviated papHCl; molar mass  378.85 g/mol) is a drug that belongs to a group of medicines called vasodilators, which cause blood vessels to expand, thereby increasing blood flow. This drug is the conjugate acid of the weak base papaverine (abbreviated pap; Kb  8.33  109 at 35.0C). Calculate the pH of a 30.0 mg/mL aqueous dose of papHCl prepared at 35.0C. Kw at 35.0C is 2.1  1014. 147

Hemoglobin (abbreviated Hb) is a protein that is responsible for the transport of oxygen in the blood of mammals. Each hemoglobin molecule contains four iron atoms that are the binding sites for O2 molecules. The oxygen binding is pH-dependent. The relevant equilibrium reaction is Use Le Chteliers principle to answer the following

The pH of human blood is steady at a value of approximately 7.4 owing to the following equilibrium reactions: Acids formed during normal cellular respiration react with the HCO3 to form carbonic acid, which is in equilibrium with CO2(aq) and H2O(l). During vigorous exercise, a persons H2CO3 blood levels were 26.3 mM, whereas his CO2 levels were 1.63 mM. On resting, the H2CO3 levels declined to 24.9. What was the CO2 blood level at rest?

A 10.0-mL sample of an HCl solution has a pH of 2.000. What volume of water must be added to change the pH to 4.000

Which of the following represent conjugate acidbase pairs? For those pairs that are not conjugates, write the correct conjugate acid or base for each species in the pair. a. H2O, OH c. H3PO4, H2PO4 b. H2SO4, SO4 2 d. HC2H3O2, C2H3O2 15

A solution is tested for pH and conductivity as pictured below: The solution contains one of the following substances: HCl, NaOH, NH4Cl, HCN, NH3, HF, or NaCN. If the solute concentration is about 1.0 M, what is the identity of the solute?

A 0.25-g sample of lime (CaO) is dissolved in enough water to make 1500 mL of solution. Calculate the pH of the solution.

At 25C, a saturated solution of benzoic acid (Ka  6.4  105 ) has a pH of 2.80. Calculate the water solubility of benzoic acid in moles per liter

Calculate the pH of an aqueous solution containing 1.0  102 M HCl, 1.0  102 M H2SO4, and 1.0  102 M HCN. 1

Acrylic acid 1CH is a precursor for many important 2CHCO2H2 CO21aq2 H2O1l2 H2CO31aq2 HCO3 1aq2 H1aq2 plastics. Ka for acrylic acid is 5.6  105 . a. Calculate the pH of a 0.10 M solution of acrylic acid. b. Calculate the percent dissociation of a 0.10 M solution of acrylic acid. Q c. Calculate the pH of a 0.050 M solution of sodium acrylate (NaC3H3O2).

Classify each of the following as a strong acid, weak acid, strong base, or weak base in aqueous solution. a. HNO2 b. HNO3 c. CH3NH2 g. d. NaOH h. Ca(OH)2 e. NH3 i. H2SO4 f. HF

The equilibrium constant Ka for the reaction is 6.0  103 . a. Calculate the pH of a 0.10 M solution of Fe(H2O)6 3. b. Will a 1.0 M solution of iron(II) nitrate have a higher or lower pH than a 1.0 M solution of iron(III) nitrate? Explain.

Rank the following 0.10 M solutions in order of increasing pH. a. HI, HF, NaF, NaI b. NH4Br, HBr, KBr, NH3 c. C6H5NH3NO3, NaNO3, NaOH, HOC6H5, KOC6H5, C6H5NH2, HNO3

Is an aqueous solution of NaHSO4 acidic, basic, or neutral? What reaction occurs with water? Calculate the pH of a 0.10 M solution of NaHSO4.

Calculate the value for the equilibrium constant for each of the following aqueous reactions.

Students are often surprised to learn that organic acids, such as acetic acid, contain OOH groups. Actually, all oxyacids contain hydroxyl groups. Sulfuric acid, usually written as H2SO4, has the structural formula SO2(OH)2, where S is the central atom. Identify the acids whose structural formulas are shown below. Why do they behave as acids, while NaOH and KOH are bases? a. SO(OH)2 b. ClO2(OH) c. HPO(OH)2

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 HCl solution. 163

Calculate the pH of a 1.0  107 M solution of NaOH in water.

Calculate [OH] in a 3.0  107 M solution of Ca(OH)2.

Consider 50.0 mL of a solution of weak acid HA  Ka (1.00  106 ), which has a pH of 4.000. What volume of water must be added to make the pH  5.000?

Making use of the assumptions we ordinarily make in calculating the pH of an aqueous solution of a weak acid, calculate the pH of a 1.0  106 M solution of hypobromous acid (HBrO, Ka  2  109 ). What is wrong with your answer? Why is it wrong? Without trying to solve the problem, tell what has to be included to solve the problem correctly.

Calculate the pH of a 0.200 M solution of C5H5NHF. Hint: C5H5NHF is a salt composed of C5H5NH and F ions. The principal equilibrium in this solution is the best acid reacting with the best base; the reaction for the principal equilibrium is

Determine the pH of a 0.50 M solution of NH4OCl. See Exercise 167

Calculate [OH] in a solution obtained by adding 0.0100 mol solid NaOH to 1.00 L of 15.0 M NH3.

What mass of NaOH(s) must be added to 1.0 L of 0.050 M NH3 to ensure that the percent ionization of NH3 is no greater than 0.0010%? Assume no volume change on addition of NaOH.

Consider 1000. mL of a 1.00  104 M solution of a certain acid HA that has a Ka value equal to 1.00  104 . How much water was added or removed (by evaporation) so that a solution remains in which 25.0% of HA is dissociated at equilibrium? Assume that HA is nonvolatile.

Calculate the mass of sodium hydroxide that must be added to 1.00 L of 1.00 M HC2H3O2 to double the pH of the solution (assume that the added NaOH does not change the volume of the solution).

Consider the species PO4 3, HPO4 2, and H2PO4 . Each ion can act as a base in water. Determine the Kb value for each of these species. Which species is the strongest base? 1

Calculate the pH of a 0.10 M solution of sodium phosphate. See Exercise 173.

Will 0.10 M solutions of the following salts be acidic, basic, or neutral? See Appendix 5 for Ka values. a. ammonium bicarbonate b. sodium dihydrogen phosphate c. sodium hydrogen phosphate d. ammonium dihydrogen phosphate e. ammonium formate

a. The principal equilibrium in a solution of NaHCO3 is Calculate the value of the equilibrium constant for this reaction.

b. At equilibrium, what is the relationship between [H2CO3] and [CO3 2]?

c. Using the equilibrium derive an expression for the pH of the solution in terms of and using the result from part b.

d. What is the pH of a solution of NaHCO3?

A 0.100-g sample of the weak acid HA (molar mass  100.0 g/mol) is dissolved in 500.0 g water. The freezing point of the resulting solution is 0.0056C. Calculate the value of Ka for this acid. Assume molarity equals molarity in this solution.

A sample containing 0.0500 mol Fe2(SO4)3 is dissolved in enough water to make 1.00 L of solution. This solution contains hydrated SO4 2 and Fe(H2O)6 3 ions. The latter behaves as an acid: a. Calculate the expected osmotic pressure of this solution at 25C if the above dissociation is negligible. b. The actual osmotic pressure of the solution is 6.73 atm at 25C. Calculate Ka for the dissociation reaction of Fe(H2O)6 3. (To do this calculation, you must assume that none of the ions goes through the semipermeable membrane. Actually, this is not a great assumption for the tiny H ion.) c

A 2.14-g sample of sodium hypoiodite is dissolved in water to make 1.25 L of solution. The solution pH is 11.32. What is Kb for the hypoiodite ion?

Isocyanic acid (HNCO) can be prepared by heating sodium cyanate in the presence of solid oxalic acid according to the equation Upon isolating pure HNCO(l), an aqueous solution of HNCO can be prepared by dissolving the liquid HNCO in water. What is the pH of a 100.-mL solution of HNCO prepared from the reaction of 10.0 g each of NaOCN and H2C2O4, assuming all of the HNCO produced is dissolved in solution? (Ka of HNCO  1.2  104 .)

A certain acid, HA, has a vapor density of 5.11 g/L when in the gas phase at a temperature of 25C and a pressure of 1.00 atm. When 1.50 g of this acid is dissolved in enough water to make 100.0 mL of solution, the pH is found to be 1.80. Calculate Ka for the acid.

Captain Kirk, of the Starship Enterprise, has been told by his superiors that only a chemist can be trusted with the combination to the safe containing the dilithium crystals that power the ship. The combination is the pH of solution A, described below, followed by the pH of solution C. (Example: If the pH of solution A is 3.47 and that of solution C is 8.15, then the combination to the safe is 3-47-8-15.) The chemist must determine the combination using only the information below (all solutions are at 25C): Solution A is 50.0 mL of a 0.100 M solution of the weak monoprotic acid HX. Solution B is a 0.0500 M solution of the salt NaX. It has a pH of 10.02. Solution C is made by adding 15.0 mL of 0.250 M KOH to solution A. What is the combination to the safe?

For the following, mix equal volumes of one solution from Group I with one solution from Group II to achieve the indicated pH. Calculate the pH of each solution. Group I: 0.20 M NH4Cl, 0.20 M HCl, 0.20 M C6H5NH3Cl, 0.20 M (C2H5)3NHCl Group II: 0.20 M KOI, 0.20 M NaCN, 0.20 M KOCl, 0.20 M NaNO2 a. the solution with the lowest pH b. the solution with the highest pH c. the solution with the pH closest to 7.00