Name Date Class ACID-BASE THEORIES

Transcription

1 19.1 ACID-BASE THEORIES Section Review Objectives Define the properties of acids and bases Compare and contrast acids and bases as defined by the theories of Arrhenius, Brønsted-Lowry, and Lewis Vocabulary monoprotic acids diprotic acids triprotic acids conjugate acid conjugate base conjugate acid base pair hydronium ion (H 3 O ) amphoteric Lewis acid Lewis base Part A Completion Use this completion exercise to check your understanding of the concepts and terms that are introduced in this section. Each blank can be completed with a term, short phrase, or number. Compounds can be classified as acids or bases according to 1. 1 different theories. An 2 acid yields hydrogen ions 2. in aqueous solution. An Arrhenius base yields 3 in aqueous 3. solution. A Brønsted-Lowry acid is a 4 donor. A Brønsted- 4. Lowry base is a proton 5. In the Lewis theory, an acid is an 5. 6 acceptor. A Lewis base is an electron-pair An acid with one ionizable hydrogen atom is called a 8 7 acid, while an acid with two ionizable hydrogen atoms is called a 8. 9 acid. 9. A 10 is a pair of substances related by the gain or loss of 10. a hydrogen ion. A substance that can act as both an acid and a base 11. is called 11. Chapter 19 Acids, Bases, and Salts 487

2 Part B True-False Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT. 12. Hydrochloric acid is a strong acid that is diprotic. 13. The ammonium ion, NH 4, is a Brønsted-Lowry base. 14. A Brønsted-Lowry base is a hydrogen-ion acceptor. 15. A compound can act as both an acid and a base. 16. PBr 3 is a Lewis base. Part C Matching Match each description in Column B to the correct term in Column A. Column A Column B 17. monoprotic acids 18. triprotic acids 19. acid properties 20. base properties a. tastes sour and will change the color of an acid-base indicator b. an electron-pair donor c. a water molecule that gains a hydrogen ion d. acids that contain three ionizable hydrogens 21. conjugate base 22. conjugate acid 23. hydronium ion (H 3 O ) 24. Lewis acid 25. Lewis base Part D Problem Answer the following in the space provided. 26. Identify the Lewis acid and Lewis base in the following reaction. Explain. H O ^ H 2 C C H H dimethyl ether e. particle that remains when an acid has donated a hydrogen ion f. an electron-pair acceptor g. acids that contain one ionizable hydrogen h. tastes bitter and feels slippery i. particle formed when a base gains a hydrogen ion F H H F C B 2 F ^ % ^ % B uy H O F ^ % F H 2 C 2 H boron trifluoride 488 Core Teaching Resources

3 19.2 HYDROGEN IONS AND ACIDITY Section Review Objectives Classify a solution as neutral, acidic, or basic, given the hydrogen-ion or hydroxide-ion concentration Convert hydrogen-ion concentrations into values of ph and hydroxide-ion concentrations into values of poh Describe the purpose of ph indicators Vocabulary self-ionization neutral solution ion-product constant for water (K w ) acidic solution basic solution alkaline solutions ph Key Equations K w [H ] [OH ] M 2 poh log [OH ] ph log [H ] ph poh 14 Part A Completion Use this completion exercise to check your understanding of the concepts and terms that are introduced in this section. Each blank can be completed with a term, short phrase, or number. Water molecules can 1 to form hydrogen ions (H ) and 1. hydroxide ions (OH ). The concentrations of these ions in pure 2. water at 25 C are both equal to 2 mol/l. 3. The ph scale, which has a range from 3, is used to 4. denote the 4 concentration of a solution. On this scale, 0 is 5. strongly 5, 14 is strongly 6, and 7 is 7. Pure 6. water at 25 C has a ph of The 9 constant for water has a value of Thus, the product of the concentrations of 10 ions and ions in aqueous solution will always equal Chapter 19 Acids, Bases, and Salts 489

4 Part B True-False Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT. 12. In an acidic solution, [H ] is greater than [OH ]. 13. ph indicators can give accurate ph readings for solutions. 14. If the [H ] in a solution increases, the [OH ] must decrease. 15. The [OH ] is less than 10 7 M in a basic solution. 16. The definition of ph is the negative logarithm of the hydroxide-ion concentration. Part C Matching Match each description in Column B to the correct term in Column A. Column A 17. alkaline solutions 18. ph 19. self-ionization 20. neutral solution Column B a. aqueous solution in which [H ] and [OH ] are equal b. product of hydrogen ion and hydroxide ion concentrations for water c. base solutions d. solution in which [H ] is less than [OH ] 21. ion-product constant for water (K w ) 22. acidic solution 23. basic solution Part D Problems e. reaction in which two water molecules produce ions f. the negative logarithm of the hydrogen-ion concentration g. solution in which [H ] is greater than [OH ] Answer the following in the space provided. 24. Calculate the hydroxide-ion concentration, [OH ], for an aqueous solution in which [H ] is mol/l. Is this solution acidic, basic, or neutral? 25. Determine the hydrogen-ion concentrations for aqueous solutions that have the following ph values. a. 3 b. 6 c Core Teaching Resources

5 19.3 STRENGTHS OF ACIDS AND BASES Section Review Objectives Define strong acids and weak acids Calculate an acid dissociation constant (K a ) from concentration and ph measurements Order acids by strength according to their acid dissociation constants (K a ) Order bases by strength according to their base dissociation constants (K b ) Vocabulary strong acids weak acids acid dissociation constant (K a ) strong bases weak bases base dissociation constant (K b ) Part A Completion Use this completion exercise to check your understanding of the concepts and terms that are introduced in this section. Each blank can be completed with a term, short phrase, or number. The strength of an acid or a base is determined by the 1 1. of the substance in solution. The acid dissociation constant, 2. 2, is a quantitative measure of acid strength. A strong acid 3. has a much 3 K a than a weak acid. The K a of an acid is 4. determined from measured 4 values. 5. Hydrochloric acid and sulfuric acid are 5 ionized in 6. solution and are 6 acids. Ethanoic acid, which is only about 7. 1 percent ionized, is a 7 acid. Magnesium hydroxide and 8. calcium hydroxide are strong Weak bases react with 9 to form the hydroxide ion and 10. the conjugate 10 of the base. Concentration in solution does 11. not affect whether an acid or a base is 11 or weak. Chapter 19 Acids, Bases, and Salts 491

6 Part B True-False Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT. 12. Acids are completely dissociated in aqueous solution. 13. Diprotic acids lose both hydrogens at the same time. 14. Acid dissociation constants for weak acids can be calculated from experimental data. 15. Bases react with water to form hydroxide ions. Part C Matching Match each description in Column B to the correct term in Column A. Column A Column B 16. strong acids 17. weak acids 18. acid dissociation constant (K a ) 19. strong bases a. ratio of the concentration of the dissociated (or ionized) form of an acid to the concentration of the undissociated acid b. bases that dissociate completely into metal ions and hydroxide ions in aqueous solution c. acids that ionize completely in aqueous solution d. bases that do not dissociate completely in aqueous solution 20. weak bases 21. base dissociation constant (K b ) Part D Problem e. acids that are only partially ionized in aqueous solution f. ratio of concentration of conjugate acid times concentration of hydroxide ion to the concentration of conjugate base Answer the following in the space provided. 22. A 0.35M solution of a strong acid, HX, has a [H ] of What is the value of K a for this acid? 492 Core Teaching Resources

7 19.4 NEUTRALIZATION REACTIONS Section Review Objectives Explain how acid base titration is used to calculate the concentration of an acid or a base Explain the concept of equivalence in neutralization reactions Vocabulary neutralization reactions equivalence point standard solution titration end point Key Equations Acid Base y Salt Water Gram equivalent mass Normality (N) equiv/l N 1 V 1 N 2 V 2 N A V A N B V B Part A Completion Use this completion exercise to check your understanding of the concepts and terms that are introduced in this section. Each blank can be completed with a term, short phrase, or number. In the reaction of a(n) 1 with a base, hydrogen ions 1. and 2 ions react to produce 3. This reaction, called 2. 4, is usually carried out by 5. The 6 in a 3. titration is the point at which the solution is neutral. At the 4. 7 molar mass number of ionizable hydrogens point of a titration, the number of equivalents of acid 5. equals the number of equivalents of base Chapter 19 Acids, Bases, and Salts 493

8 Part B True-False Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT. 8. A solution of known concentration is called a standard solution. 9. The end point of a titration of a strong base with a strong acid occurs when [H ] [OH ]. 10. The point of neutralization is the end point of titration. 11. The reaction of an acid and a base produces only water. Part C Matching Match each description in Column B to the correct term in Column A. Column A Column B 12. titration 13. neutralization reactions 14. equivalence point 15. standard solution a. when the number of moles of hydrogen ions equals the number of moles of hydroxide ions b. a solution of known concentration c. a process for determining the concentration of a solution by adding a known amount of a standard solution d. point of neutralization 16. end point Part D Problem Answer the following in the space provided. 17. Complete and balance the equations for the following acid base reactions. a. H 3 PO 4 Al(OH) 3 b. HI Ca(OH) 2 e. reactions between acids and bases to produce a salt and water 494 Core Teaching Resources

9 19.5 SALTS IN SOLUTION Section Review Objectives Define when a solution of a salt is acidic or basic Demonstrate with equations how buffers resist changes in ph Vocabulary salt hydrolysis buffers buffer capacity Part A Completion Use this completion exercise to check your understanding of the concepts and terms that are introduced in this section. Each blank can be completed with a term, short phrase, or number. A 1 forms when an acid is neutralized by a base. Salts 1. can be neutral, 2, or 3 in solutions. Salts of strong 2. acid strong base reactions produce 4 solutions with water. 3. Salts formed from the neutralization of weak acids or weak bases 4. 5 water. They produce solutions that are acidic or basic. 5. For example, the ph of a solution at the equivalence point is 6. greater than 7 for a 6 base- 7 acid titration. Solutions 7. that resist changes in ph are called 8 solutions. The buffer 8. 9 is the amount of acid or base that can be added to a buffer 9. without changing the ph greatly. Chapter 19 Acids, Bases, and Salts 495

10 Part B True-False Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT. 10. An aqueous solution of NH 4 Cl is basic. 11. HCl NaCl would be a good buffer system. 12. A buffer is a solution of a weak acid and one of its salts. 13. A strong acid and a weak base produce an acidic solution. Part C Matching Match each description in Column B to the correct term in Column A. Column A Column B 14. salt hydrolysis 15. buffer 16. buffer capacity 17. NH 4 Cl a. the cations or anions of a dissociated salt remove hydrogen ions from or donate hydrogen ions to water b. the amount of acid or base that can be added to a buffer solution before a significant change in ph can occur c. the salt produced by the titration of ammonia with hydrochloric acid. Part D Question Answer the following in the space provided. 18. Predict whether an aqueous solution of each salt will be acidic, basic, or neutral. a. NH 4 Cl b. Na 2 CO 3 c. NH 4 NO 3 d. a solution in which the ph remains relatively constant when small amounts of acid or base are added 496 Core Teaching Resources

11 19 ACIDS, BASES, AND SALTS Practice Problems In your notebook, solve the following problems. SECTION 19.1 ACID BASE THEORIES 1. Identify the hydrogen ion donor(s) and hydrogen ion acceptor(s) for ionization of H 2 SO 4 in water. Label the conjugate acid base pairs. 2. Identify all of the ions that may be formed when H 3 PO 4 ionizes in water. 3. Classify the following acids as monoprotic, diprotic, or triprotic. a. HCOOH b. HBr c. H 2 SO 3 d. H 3 ClO 4 4. What would you expect to happen when lithium metal is added to water? Show the chemical reaction. 5. In the following chemical reaction, identify the Lewis acid and base. BF 3 F 1 BF 4 6. Describe some distinctive properties of acids. 7. Describe some distinctive properties of bases. SECTION 19.2 HYDROGEN IONS AND ACIDITY 1. A solution has a hydrogen ion concentration of M. What is its ph? 2. What is the ph of a solution if the [H ] M? 3. What is the poh of a solution if the [OH ] M? 4. What is the poh of a solution that has a ph of 3.4? 5. Classify each solution as acidic, basic, or neutral. a. [H ] M d. [H ] M b. poh 12.0 e. ph 0.8 c. [OH ] M 6. Calculate the ph of each solution. a. [H ] M c. [OH ] M b. [H ] M d. poh Classify the solutions in problem 6 as acidic or basic. 8. Why is there a minus sign in the definition of ph? 9. A solution has a poh of What is the ph of this solution? 10. What is the ph of a solution with [H ] M? Chapter 19 Acids, Bases, and Salts 497

12 SECTION 19.3 STRENGTHS OF ACIDS AND BASES 1. Rank 1M of these compounds in order of increasing hydrogen ion concentration: weak acid, strong acid, strong base, weak base. 2. Write the expression for the acid dissociation constant of the strong acid hydrofluoric acid, HF. 3. Write the expression for the base dissociation constant for hydrazine, N 2 H 4, a weak base. Hydrazine reacts with water to form the N 2 H 5 ion. 4. Use Table 19.8 in your textbook to rank these acids from weakest to strongest: HOOCCOOH, HCO 3, H 2 PO 4, HCOOH. 5. Write the equilibrium equation and the acid dissociation constant for the following weak acids. a. H 2 S b. NH 4 c. C 6 H 5 COOH 6. Match each solution with its correct description. a. dilute, weak acid (1) 18M H 2 SO 4 (aq) b. dilute, strong base (2) 0.5M NaOH(aq) c. concentrated, strong acid (3) 15M NH 3 (aq) d. dilute, strong acid (4) 0.1M HC 2 H 3 O 2 (aq) e. concentrated, weak base (5) 0.1M HCl(aq) 7. Write the base dissociation constant expression for the weak base analine, C 6 H 5 NH 2. C 6 H 5 NH 2 (aq) H 2 O(l) 1 C 6 H 5 NH 3 (aq) OH (aq) 8. A 0.10M solution of formic acid has an equilibrium [H ] M. HCOOH(aq) H (aq) HCOO (aq) What is the K a of formic acid? 9. The K a of benzoic acid, C 6 H 5 COOH, is What is the equilibrium [H ] in a 0.20M solution of benzoic acid? 10. A 0.10M solution of hydrocyanic acid, HCN, has an equilibrium hydrogen ion concentration of M. What is the K a of hydrocyanic acid? 498 Core Teaching Resources

13 SECTION 19.4 NEUTRALIZATION REACTIONS 1. What is the molarity of a sodium hydroxide solution if 38 ml of the solution is titrated to the end point with 14 ml of 0.75M sulfuric acid? 2. If 24.6 ml of a Ca(OH) 2 solution is needed to neutralize 14.2 ml of M HC 2 H 3 O 2, what is the concentration of the calcium hydroxide solution? 3. A 12.4 ml solution of H 2 SO 4 is completely neutralized by 19.8 ml of M Ca(OH) 2. What is the concentration of the H 2 SO 4 solution? 4. What volume of 0.12M Ba(OH) 3 is needed to neutralize 12.2 ml of 0.25M HCl? 5. A 55.0-mg sample of Al(OH) 3 is reacted with 0.200M HCl. How many milliters of the acid are needed to neutralize the Al(OH) 3? SECTION 19.5 SALTS IN SOLUTION 1. A buffer solution is prepared by mixing together equal quantities of formic acid, HCHO 2, and sodium formate, NaCHO 2. Write equations that show what happens when first acid, and then base, is added to this buffer solution. 2. Complete the following rules. a. strong acid strong base y c. weak acid strong base y b. strong acid weak base y Chapter 19 Acids, Bases, and Salts 499

14 19 INTERPRETING GRAPHICS Use with Section ph M NaOH added (ml) Figure 1 The ph curve for the titration of a benzoic acid (C 6 H 5 COOH) solution with a standard solution of 0.10M sodium hydroxide (NaOH). The plot shown in Figure 1 shows how the ph of a benzoic acid solution of unknown concentration changes as a function of the volume of 0.10M NaOH added. The starting volume of benzoic acid solution was 25 ml. Use this titration curve to answer the following questions. 1. Write the chemical equation for the reaction of benzoic acid (C 6 H 5 COOH) with NaOH. Note that the acidic hydrogen atom in benzoic acid is shown in bold. How many moles of benzoic acid are neutralized per mole of NaOH added? 2. Estimate the ph of the solution at the equivalence point of the titration. Is the solution acidic, neutral, or basic at the equivalence point? 3. Based on your estimate of the ph at the equivalence point, characterize benzoic acid as a weak acid or a strong acid. Explain your answer. 4. How many moles of NaOH were needed to reach the equivalence point? 500 Core Teaching Resources

15 5. Define the equivalence point in this reaction. What are [NaOH], [C 6 H 5 COOH], and [C 6 H 5 COONa] at the equivalence point? 6. What is the concentration of benzoic acid in the original unknown solution? 7. Refer to Figure 19.8 in your textbook. Which of the acid base indicators shown would be most appropriate for this particular titration? Label the titration curve in Figure 1 to indicate the range of ph values for which your chosen indicator is most effective. 8. At the equivalence point, the ph of the solution is determined by the hydrolysis of the sodium benzoate salt, C 6 H 5 COONa. Write the chemical equation showing the hydrolysis of water by the benzoate ion (C 6 H 5 COO ). How does this equation support your answer to question 2? 9. Use your answer to question 8 to write the base dissociation constant (K b ) expression for the reaction of benzoate ion with water. 10. Based on your estimate of the ph at the equivalence point and using the expression for K b, determine the numerical value of K b for the benzoate ion (C 6 H 5 COO ). Chapter 19 Acids, Bases, and Salts 501

16 19 ACIDS, BASES, AND SALTS Vocabulary Review From each group of terms, choose the term that does not belong and then explain your choice. 1. basic, neutral, acidic, hydronium ion 2. acidic solution, hydroxide ion, basic solution, alkaline solution 3. Arrhenius, Brønsted-Lowry, Lewis, amphoteric 4. conjugate acid, Brønsted-Lowry, Lewis acid, conjugate base 5. weak bases, weak acids, strong acids, dissociation constant Choose the term from the following list that best matches each description. equivalence point neutral hydrolyzing salts buffer 6. compounds derived from the reaction of a strong base with a weak acid or from the reaction of a strong acid with a weak base 7. a term used to describe the ph of a solution that results when one equivalent of a strong acid is mixed with one equivalent of a strong base 8. the point of neutralization in a titration 9. a solution that consists of a weak acid and one of its salts, or a solution of a weak base and one of its salts 502 Core Teaching Resources

17 19 ACIDS, BASES, AND SALTS Chapter Quiz Choose the best answer and write its letter on the line. 1. A solution in which the hydroxide-ion concentration is is 19.2 a. acidic. c. neutral. b. basic. d. none of the above 2. What is the ph of a solution in which [OH ] ? 19.2 a. 5.0 c. 5.0 b. 9.0 d If the [H ] in a solution is mol/l, then the [OH ] is 19.2 a mol/l. c mol/l. b mol/l. d. cannot be determined 4. In the reaction: 19.1 CO 2 3 H 2 O 1 HCO 3 OH the carbonate ion is acting as a(n) a. Arrhenius base. c. Brønsted-Lowry base. b. Arrhenius acid. d. Brønsted-Lowry acid. _ 5. Identify the Brønsted-Lowry base and conjugate base in this reaction H 2 S H 2 O 1 H 3 O HS a. H 2 S and H 2 O c. HS and H 2 O b. H 2 S and H 3 O d. HS and H 3 O 6. For the reaction HX 1 H X, the equilibrium concentrations 19.3 are as follows. [HX] ; [H ], [X ] K a would be: a c b d The reaction that takes place when an acid is added to an ethanoic 19.5 acid-ethanoate (CH 3 COOH/CH 3 COO ) buffer is a. CH 3 COO H 1 CH 4 CO 2 b. CH 3 COOH H 1 CH 3 COO H c. CH 3 COO H 1 CH 3 COOH d. CH 3 COOH OH 1 CH 3 COO H 2 O 8. Which salt hydrolyzes water to form a solution that is acidic? 19.5 a. LiBr c. NaBr b. NH 4 Br d. KBr Chapter 19 Acids, Bases, and Salts 503

18 19 ACIDS, BASES, AND SALTS Chapter Test A A. Matching Match each term in Column B with the correct description in Column A. Write the letter of the correct term on the line. Column A Column B 1. acid dissociation constant a. acidic solution 2. [H ] greater than [OH ] b. conjugate acid base pair 3. The cations or anions of a dissociated salt remove hydrogen ions from or donate hydrogen ions to water. 4. point of neutralization of the titration 5. H 3 O 6. [OH ] and [H ] c. amphoteric d. alkaline solution e. K w f. end point 7. [OH ] greater than [H ] g. neutral solution 8. ion-product constant for water 9. describes a substance that can act as both an acid and a base 10. two substances that are related by the loss or gain of a single hydrogen ion B. Multiple Choice Choose the best answer and write its letter on the line. 11. A solution in which the hydroxide-ion concentration is M is a. acidic. c. neutral. b. basic. d. none of the above 12. In a neutral solution, the [H ] is a c M. b. zero. d. equal to [OH ]. h. hydronium ion i. K a j. salt hydrolysis 13. The products of the self-ionization of water are a. H 3 O 7 and H 2 O. c. OH and H. b. HO and OH. d. OH and H. 504 Core Teaching Resources

19 14. Which of these solutions is most basic? a. [H ] c. [H ] b. [OH ] d. [OH ] The formula of the hydrogen ion is often written as a. H 2 O. c. H. b. OH. d. H 3 O. 16. What is the ph of a solution in which the [H ] ? a. 1.0 c. 2.0 b. 2.0 d What is the ph of a 0.01M hydrochloric acid solution? a c. 2.0 b d The K a of carbonic acid is H 2 CO 3 1 H HCO 3 This means that H 2 CO 3 is a a. good hydrogen-ion acceptor. b. poor hydrogen-ion acceptor c. good hydrogen-ion donor. d. poor hydrogen-ion donor. 19. Which of the following pairs consist of a weak acid and a strong base? a. ethanoic acid, sodium hydroxide b. ethanoic acid, calcium hydroxide c. sulfuric acid, sodium hydroxide d. ethanoic acid, ammonia 20. In the reaction NH 4 H 2 O 1 NH 3 H 3 O, water is acting as a(n) a. Arrhenius acid. c. Brønsted-Lowry acid. b. Brønsted-Lowry base. d. Arrhenius base. 21. A solution with a ph of 5.0 a. is basic. b. has a hydrogen-ion concentration of 5.0M. c. is neutral. d. has a hydroxide-ion concentration of M. 22. With solutions of strong acids and strong bases, the word strong refers to a. molality. c. solubility. b. molarity. d. degree of ionization. 23. The hydrolysis of water by the salt of a weak base and a strong acid should produce a solution that is a. weakly basic. c. strongly basic. b. neutral. d. acidic. 24. Which of these is an Arrhenius base? a. KOH c. H 2 PO 4 b. NH 3 d. CH 3 COOH Chapter 19 Acids, Bases, and Salts 505

20 25. Which of these acids is monoprotic? a. CH 3 COOH c. H 2 SO 4 b. H 2 CO 3 d. H 3 PO A solution that contains one mole of Ca(OH) 2 and one mole of H 2 SO 4 is a. CaSO 4 H 3 O H 2 O. c. CaH 2 H 3 SO 4. b. CaSO 4 H 3 O OH. d. CaSO 4 2H 2 O. 27. According to the Brønsted-Lowry theory, water a. acts as a base when it accepts a hydrogen ion. b. can be neither an acid nor a base. c. acts as an acid by accepting hydrogen ions. d. can accept but not donate hydrogen ions. 28. What are the Brønsted-Lowry acids in this equilibrium reaction? CN H 2 O 1 HCN OH a. H 2 O, OH c. H 2 O, HCN b. CN, OH d. CN, H 2 O 29. A solution of one of the following compounds is acidic because one of its ions undergoes hydrolysis. The compound is a. KCl. c. CH 3 COOK. b. NH 4 Cl. d. NH 3. C. Problems Solve the following problems in the space provided. Show your work. 30. Calculate the ph for the following solutions. State whether each solution is acidic, basic, or neutral. a. [H ] b. [OH ] c. [H ] Calculate the hydrogen-ion concentration [H ] for an aqueous solution in which [OH ] is mol/l. Is this solution acidic, basic, or neutral? 506 Core Teaching Resources

21 32. Write the expression for K a for each acid. Assume that only one hydrogen is ionized in each case. a. H 2 SO 3 b. HNO Write complete and balanced equations for each of the following acid base reactions. a. HBr Mg(OH) 2 y b. H 2 SO 4 Al(OH) 3 y 34. Predict whether an aqueous solution of each salt will be acidic, basic, or neutral. a. Na 2 CO 3 c. (NH 4 )SO 4 b. KNO 3 d. Mg(C 2 H 3 O 2 ) 2 D. Essay Write a short essay for the following. 35. Compare and contrast the properties of acids and bases. Chapter 19 Acids, Bases, and Salts 507

22 19 ACIDS, BASES, AND SALTS Chapter Test B A. Matching Match each term in Column B with the correct description in Column A. Write the letter of the correct term on the line. Column A Column B 1. a substance that can donate a pair of electrons to form a covalent bond 2. a compound that produces hydroxide ions when dissolved in water 3. the particle formed when a weak base gains a hydrogen ion a. the ion-product constant for water b. Lewis base c. acid (mol/l) 2 d. conjugate acid 5. a substance that can accept a pair of electrons to form a covalent bond 6. a compound that produces hydrogen ions when dissolved in water e. neutralization reaction f. Lewis acid 7. H 2 SO 4 8. when the number of moles of hydrogen ions equals the number of moles of hydroxide ions in titration 9. describes a substance that can act as both an acid and a base 10. the process of adding a known amount of solution of known concentration to determine the concentration of another solution 11. reactions in which an acid and a base react in an aqueous solution to produce a salt and water B. Multiple Choice Choose the best answer and write its letter on the line. 12. Which of the following is true about acids? a. Acids give foods a bitter taste. b. Aqueous solutions of acids conduct electricity. c. Acids have a ph value greater than 7. d. all of the above 508 Core Teaching Resources g. base h. diprotic acid i. amphoteric j. titration k. equivalence point

23 13. The products of the neutralization reaction between HNO 2 (aq) and Ca(OH) 2 (aq) are a. CaNO 3 H 2 O. c. CaNO 3 2H 2 O. b. Ca(NO 3 ) 2 H 2 O. d. Ca(NO 3 ) 2 2H 2 O. 14. A solution in which the [H ] is mol/l is said to be a. acidic. c. neutral. b. basic. d. none of the above 15. What is the ph of the solution in question 14? a c b d A solution with a ph of 9 has a [OH ] concentration of a mol/l. c mol/l. b mol/l. d mol/l. 17. Among the following, which solution is the most acidic? a. [H ] mol/l c. [OH ] mol/l b. ph 3 d. ph The monoprotic acid from among the following is a. H 2 CO 3. c. H 3 PO 4. b. H 2 SO 4. d. HCl. 19. The Brønsted-Lowry theory defines an acid as a(n) a. hydrogen ion donor. c. electron-pair donor. b. hydrogen ion acceptor. d. electron-pair acceptor. 20. Which of the following is true about neutralization reactions? a. They involve strong acids and strong bases. b. They result in the production of a salt and water. c. They are all double-replacement reactions. d. all of the above 21. In the reaction: HCl(g) NH 3 (aq) NH 4 (aq) Cl (aq), HCl(g) is acting as a(n): a. Brønsted-Lowry acid. c. Lewis acid. b. Brønsted-Lowry base. d. Lewis base. 22. The conjugate acid in the reaction described in question 21 is a. HCl(g). c. NH 4 (aq). b. NH 3 (aq). d. Cl (aq). 23. Which of the following is true about indicators? a. They are weak acids or bases. b. They are as accurate as a ph meter. c. They maintain their colors across the range of ph values for which they are used. d. all of the above Chapter 19 Acids, Bases, and Salts 509

24 24. What is the Lewis acid in the following reaction? NH 3 BI 3 I 3 BNH 3 a. NH 3 c. I 3 BNH 3 b. BI 3 d. none of these 25. Among the following K a values, which represents the strongest acid? a. K a c. K a b. K a d. K a How many moles of Mg(OH) 2 (aq) would be required to neutralize 3.0 mol HCl(aq)? a. 1.5 mol c. 6.0 mol b. 3.0 mol d. 2.0 mol C. Problems Solve the following problems in the space provided. Show your work. 27. Calculate the [OH ] for an aqueous solution in which [H ] mol/l. Is the solution acidic, basic, or neutral? 28. For each of the following, fill in the concentration of the requested ion, the ph, and the type of solution (acid, base, or neutral). a. [H ] [OH ] Concentration ph Solution Type b. [OH ] [H ] c. [H ] [OH ] [H ] 29. Write the expression for K a for each of the following acids. Assume that only one hydrogen is ionized. a. HI b. H 2 SO Write complete and balanced equations for each of the following neutralization reactions: a. HF(aq) KOH(aq) y b. H 2 SO 4 (aq) LiOH(aq) y 31. How many moles of sulfuric acid would be required to neutralize 0.35 mol of KOH? 510 Core Teaching Resources

25 32. If the K sp for a CuCl solution is , what is the concentration of Cu and of Cl ions at equilibrium? D. Essay Write a short essay for the following. 33. Distinguish between the Brønsted-Lowry and Lewis theories of acids and bases. E. Additional Problems Solve the following problems in the space provided. Show your work. 34. Determine the ph of a solution whose [H ] mol/l. Is the solution acidic, basic, or neutral? 35. Use the Brønsted-Lowry definitions of acids and bases to identify the acid, base, conjugate acid, and conjugate base in each of the following reactions. a. HF(aq) H 2 O(l) 1 H 3 O (aq) F (aq) b. HCl(g) H 2 O(l)1 H 3 O (aq) Cl (aq) c. HC 2 H 3 O 2 (aq) H 2 O(l) 1 H 3 O (aq) C 2 H 3 O 2 (aq) a. b. c. Acid Base Conjugate Acid Conjugate Base 36. Identify the Lewis acids and bases in the following reactions: a. H I HI b. NH 3 BCl 3 Cl 3 BNH 3 Lewis Acid Lewis Base 37. A M solution of ethanoic acid (HC 2 H 3 O 2 ) is only partially ionized so that [H ] M. What is the acid dissociation constant for this acid? Chapter 19 Acids, Bases, and Salts 511