MULTIPLE CHOICE QUESTIONS Part 3: Syror och baser (Answers on page 18)

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1 MULTIPLE CHICE QUESTINS Part 3: Syror och baser (Answers on page 18) Topic: Acid-Base Definitions 1. According to the Lewis definition, a base is a(n): A) Proton donor. B) Electron pair donor. C) Hydroxide ion donor. D) Hydrogen ion donor. E) Electron pair acceptor. 2. Which of the following is not both a Bronsted-Lowry acid and a Bronsted-Lowry base? A) HS 4 B) H 2P 4 C) HC 3 D) H E) SH 3. Which of the following is not a conjugate acid - conjugate base pair (in that order)? A) H 3P 4, H 2P 4 B) HBF 4, BF 4 C) CH 3CH 2H, CH 3CH 2 D) H 3 +, H 2 E) HP 4, H 2P 4 4. The conjugate base of sulfuric acid is: A) H 3S 4 + B) S 3 C) HS 4 D) H 2S 3 E) HS 3 Topic: Acid-Base Definitions 6. Which of these is not a true statement? A) All Lewis bases are also Bronsted-Lowry bases. B) All Lewis acids contain hydrogen. C) All Bronsted-Lowry acids contain hydrogen. D) All Lewis acids are electron deficient. E) According to the Bronsted-Lowry theory, water is both an acid and a base. 7. For the equilibrium CH 3NH H 2 CH 3NH H 3 + the two substances which both are acids are: A) H 2 and H 3 + B) CH 3NH 3 + and H 2 C) CH 3NH 3 + and CH 3NH 2 D) CH 3NH 3 + and H 3 + E) CH 3NH 2 and H 2 8. Which of the following is not a Lewis base? A) NH 3 B) H C) BF 3 D) H 2 E) H 3C 9. Which of the following is not a Bronsted-Lowry acid? A) H 2 B) (CH 3) 3N C) NH 4 + D) CH 3C 2H E) HC"CH 5. Consider the equilibrium. Which are the Bronsted-Lowry bases? P H 2 HP H - A) P 4 3 and HP 4 2 B) P 4 3 and H C) P 4 3 and H 2 D) H 2 and H E) H 2 and HP The reaction between which combination of substances below cannot be classified as a Bronsted-Lowry acid-base reaction? A) CH 3Li + C 2H 5H B) H 2S 4 + CH 3C 2Na C) BF 3 + NH 3 D) H CH 3NH - E) two of the above 2

2 Topic: Acid-Base Definitions 11. Which of these is not a Lewis acid? A) AlCl 3 B) H 3 + C) FeCl 3 D) S 3 E) C 4H 10 Topic: Acid-Base Reactions 16. Adding sodium hydride to ethanol would produce: A) CH 3CH 2CH 2CH 3 + H 2 D) CH 3CH 2Na + NaH B) CH 3CH 2CH 2CH 3 + NaH E) CH 3CH 3 + NaH C) CH 3CH 2Na + H 2 D)CH 3CH 2Na + NaH E) CH 3CH 3 + NaH 12. This species is a carbon-based Lewis acid: A) CH 4 B) HCCl 3 C) CH 3 + D) :CH 3 E) CH Adding sodium amide (NaNH 2) to 1-butyne (CH 3CH 2C CH) would produce: A) CH 3CH 2C CNa + NH 3 B) CH 3CH 2C C-C CH 2CH 3 + NaH + NH 3 C) CH 3CH 2C CNH 2 + NaH D) NaCH 2CH 2C CH + NH 3 E) CH 3CH(Na)C CH + NH What is the conjugate base of ethanol? A) CH 3CH 2 B) CH 3CH 2 C) CH 3CH 2H 2 + D) CH 3CH 3 E) CH 3CH Which acid-base reaction would not take place as written? A) CH 3Li + CH 3CH 2H ####$ CH 4 + CH 3CH 2Li B) HC"CH + NaH ####$ HC"CNa + H 2 C) HC"CNa + H 2 ####$ HC"CH + NaH D) CH 3H + NaH ####$ CH 3Na + H 2 E) CH 3C 2H + CH 3Na ####$ CH 3C 2Na + CH 3H 14. Which of the acids below would have the strongest conjugate base? A) CH 3CH 2H pk a = 18 B) CH 3C 2H pk a = 4.75 C) ClCH 2C 2H pk a = 2.81 D) Cl 2CHC 2H pk a = 1.29 E) Cl 3CC 2H pk a = Which of the following is a Lewis acid? A) H 3 + B) BF 3 C) NF 3 D) H E) N"N 19. Which acid-base reaction would not take place as written? A) CH 3Li + CH 3CH 2CH 2CH 2NH 2 ####$ CH 4 + CH 3CH 2CH 2CH 2NHLi B) CH 3C"CH + NaCH 3 ####$ HC"CNa + CH 3H C) HC"CNa + H 2 ####$ HC"CH + NaH D) CH 3H + NaNH 2 ####$ CH 3Na + NH 3 E) CH 3C 2H + CH 3Na ####$ CH 3C 2Na + CH 3H 20. Which acid-base reaction would not take place as written? A) CH 3Li + CH 3CH 2H ####$ CH 4 + CH 3CH 2Li B) H 2C=CH 2 + NaH ####$ H 2C=CHNa + H 2 C) CH 3C CNa + H 2 ####$ CH 3C CH + NaH D) (CH 3) 2CHH + NaH ####$ (CH 3) 2CHNa + H 2 E) CH 3C 2H + CH 3Na ####$ CH 3C 2Na + CH 3H 3 4

3 Topic: Acid-Base Reactions 21. The amide ion, NH 2, is a base which can be used only in which of the solvents shown below: A) CH 3H B) CH 3CH 2H C) H 2 D) D 2 E) Liquid NH 3 Topic: Acid-Base Reactions 26. Which reaction of these potential acids and bases does not occur to any appreciable degree due to an unfavorable equilibrium? A) NaNH 2 + CH 3CH 2CH 2CH 2CH 2CH 3 B) CH 3CH 2C 2Na + HI C) CH 3Li in hexane + ethyne D) NaH + methanol E) Two of the above will not occur 22. Acetic acid dissociates most completely in: A) CCl 4 B) Cl 2C=CCl 2 C) H 2 D) (CH 3CH 2) 2 E) the gas phase. 23. Which pair of species are both bases in the following reaction? HCN and H 2 H 3 + and CN A) H 2 and CN B) H 3 + and H 2 C) HCN and H 3 + D) HCN and CN E) H 3 + and CN 27. Which reaction of these potential acids and bases does not occur to any appreciable degree due to an unfavorable equilibrium? A) NaNH 2 + CH 3CH 2CH 2CH 2CH 2H B) CH 3CH 2C 2H + NaCl C) NaHC 3 + CH 3CH 2C 2H D) NaH + CH 3CH 2CH 2CH 2CH 2NH 2 E) all of the above will occur due to a favorable equilibrium 28. Which combination of reagents is the least effective in generating sodium ethoxide, CH 3CH 2Na? A) CH 3CH 2H + NaH B) CH 3CH 2H + NaNH 2 C) CH 3CH 2H + NaH D) CH 3CH 2H + CH 3Li E) CH 3CH 2H + HC"CNa 24. What compounds are produced when sodium nitrate is added to a mixture of water and ethanol? A) HN 3 + NaH B) HN 3 + CH 3CH 2Na C) NaH + CH 3CH 2Na D) CH 3CH 2CH 2CH 3 + NaH E) No reaction occurs. 29. Which combination of reagents is effective in generating sodium ethoxide, CH 3CH 2Na? A) CH 3CH 2H + KH B) CH 3CH 2H + NaNH 2 C) CH 3CH 2H + Na D) Two of the above E) All of the above 25. Which reaction of these potential acids and bases does not occur to any appreciable degree due to an unfavorable equilibrium? A) NaH (aq) + CH 3CH 2CH 2C 2H B) CH 3CH 2Na in ethanol + ethene C) CH 3Li in hexane + ethyne D) NaNH 2 in liq. NH 3 + ethanol E) NaC 2H 3 2 (aq) + HI 30. Which combination of reagents is effective in generating sodium propynide, CH 3C CNa? A) CH 3C CH + KH B) CH 3C CH + (CH 3) 2CHNa C) CH 3C CH + C 2H 5Li D) Two of the above E) All of the above 5 6

4 Topic: Acid-Base Reactions 31. In the reaction, Na + NH 2 + CH 3H ##$ CH 3 Na + + NH 3, the stronger base is: A) NaNH 2 B) CH 3H C) CH 3Na D) NH 3 E) This is not an acid-base reaction. Topic: Acid-Base Reactions, isotope labeling, Relative acid/base strength 36. A product of the reaction, CH 3CH 2Li + D 2 ####$ is A) CH 3CH 2D B) CH 3CH 2CH 2CH 3 C) CH 2=CH 2 D) CH 3CH 2D E) CH 3CH 2CH 2CH Which sequence is the best one to use to prepare CH 3C"CD? A) NaH D CH 3 C CH 2 B) CH 3 C CH NaH D 2 C) CH 3Na D CH 3 C CH 2 D) DH CH 3 C CH E) None of these will be successful. 33. Adding sodium hydride, NaH, to water produces: A) H 2 and NaH(aq) B) H - (aq) + Na + (aq) C) H 3 + (aq) + Na + (aq) D) H 3 (aq) + Na + (aq) E) Na 2 + H Adding methyllithium, CH 3Li, to ethanol produces: A) CH 3CH 2Li + CH 3H B) CH 3CH 2Li + CH 4 C) CH 3CH 2CH 3 + LiH D) All of the above E) No reaction takes place 35. Which reaction will yield CH 3CH 2-D? A) CH 3CH 3 + D 2 B) CH 3CH 2Li + D 2 C) CH 3CH 2Li + D 2 D) CH 3CH 2H + D 2 E) More than one of these 37. The compounds ethane, ethene, and ethyne exhibit this order of increasing acidity: A) Ethyne < ethene < ethane B) Ethene < ethyne < ethane C) Ethane < ethyne < ethene D) Ethane < ethene < ethyne E) Ethene < ethane < ethyne 38. Which is an incorrect statement? A) RSH compounds are stronger acids than RH compounds. B) PH 3 is a weaker base than NH 3. C) NH 2 is a stronger base than H. D) H is a stronger base than R. E) H is a stronger base than R. 39. The correct sequence of the ions shown, in order of increasing basicity, is: A) CH 3CH 2: < CH 2=CH: < HC"C: B) CH 3CH 2: < HC"C: < CH 2=CH: C) HC"C: < CH 3CH 2: < CH 2=CH: D) CH 2=CH: < HC"C: < CH 3CH 2: E) HC"C: < CH 2=CH: < CH 3CH 2: Topic: Solvent effects 40. Which is a protic solvent? A) CCl 4 B) HCCl 3 C) CH 3H D) CH 3(CH 2) 4CH 3 E) CH 3CH 2CH 2CH 3 7 8

5 Topic: Solvent effects 41. A) B) C) Which might be used as protic solvent? H 2 N D) N E) 42. Which of the following classes of substances cannot be used as protic solvents? A) esters B) aldehydes C) ketones D) carboxylic acids E) two of the above Topic: Acid constants 43. If a 0.01 M solution of a weak acid has a ph of 4.0, the pk a of the acid is: A) 10.0 B) 8.0 C) 6.0 D) 4.0 E) 2.0 Topic: General 44. Which one of the following is a true statement? A) The stronger the acid, the larger is its pk a. B) The conjugate base of a strong acid is a strong base. C) Acid-base reactions always favor the formation of the stronger acid and the stronger base. D) Strong acids can have negative pk a values. E) Hydrogen need not be present in the molecular formula of a Bronsted-Lowry acid. Topic: Relative acid/base strengths 45. The basic species are arranged in decreasing order of basicity in the sequence: A) F > CH 3 > NH 2 > CH 3CH 2 B) CH 3 > CH 3CH 2 > NH 2 > F C) CH 3CH 2 > NH 2 > CH 3 > F D) NH 2 > CH 3CH 2 > F > CH 3 E) NH 2 > CH 3 > CH 3CH 2 > F Topic: pka calculations 46. A particular acid has K a = 2.0 x 10-5 (in aqueous solution). The evaluation of which of these expressions gives the value for pk a? A) /2.0 x 10-5 B) (2.0 x 10-5 ) C) 5 log 2.0 D) -5 + log 2.0 E) 2.0 x 10-5 /10-14 Topic: Solvent effects 47. As a consequence of the "leveling effect," the strongest acid which can exist in appreciable concentration in aqueous solution is: A) H 3 + B) H 2S 4 C) HCl 4 D) HCl E) HN 3 Topic: Relative acid/base strengths 48. Based on the position of the central atom in the periodic chart, we predict that the strongest acid of the following is: A) H 2 B) H 2S C) H 2Se D) H 2Te Topic: Acid dissociation, thermodynamic calculations 49. An acid, HA, has the following thermodynamic values for its dissociation in water at 27º C: %H = -8.0 kj mol -1 ; %S = -70 kj K -1 mol -1. The %G for the process is: A) +29 kj mol -1 B) +13 kj mol -1 C) -6.1 kj mol -1 D) -13 kj mol -1 E) -29 kj mol

6 Topic: Relative acid/base strengths, solvent effects 50. Which of these bases is the strongest one which can be used (and retains its basic character) in aqueous solution? A) CH 3 B) F C) H D) C 2H 3 2 E) HS 4 Topic: Acidity constant- thermodynamic principles 51. The acidity constant, K a, differs from the equilibrium constant, K eq, for the dissociation of the same acid in water at the same temperature and concentration in what way? A) K a can be determined experimentally with less accuracy than K eq. B) The two terms are identical numerically. C) K a is used for strong acids only; K eq for weak acids. D) K a is the reciprocal of K eq. E) K eq = K a/[h 2]. Topic: Acids/bases-general principles 52. Which of the following is an untrue statement? A) The % dissociation of a weak acid increases with increasing dilution of the acid solution. B) The stronger an acid, the weaker its conjugate base. C) The larger the value of K a for an acid, the smaller the value of its pk a. D) Comparison of the acidity of strong acids in solution requires the use of a solvent less basic than water. E) The stronger the acid, the more positive the value of %Gº for the dissociation. Topic: Acid-base reactions 53. When proton transfer reactions reach equilibrium, there have been formed: A) the weaker acid and the weaker base. B) the weaker acid and the stronger base. C) the stronger acid and the weaker base. D) the stronger acid and the stronger base. E) All proton transfers go to completion; they are not equilibrium processes. Topic: Relative acid-base strengths 54. For the simple hydrides, MH n, pk a values decrease in the order: A) CH 4 > NH 3 > H 2 > H 2S > HBr B) HBr > H 2S > H 2 > NH 3 > CH 4 C) HBr > H 2 > NH 3 > H 2S > CH 4 D) NH 3 > H 2S > CH 4 > H 2 > HBr E) H 2S > H 2 > HBr > NH 3 > CH 4 Topic: Relative acid-base strengths, solvent effects 55. The compound aniline, C 6H 5NH 2, has weakly basic properties in aqueous solution. In this other solvent, aniline would behave as a strong base. A) CH 3H B) CH 3CH 2H C) CF 3C 2H D) Liquid NH 3 E) CH 3(CH 2) 4CH Which of the following organic compounds is the strongest acid? A) C 6H 12 pk a = 52 B) CH 3CH 3 pk a = 50 C) CH 3CH 2H pk a = 18 D) CH 3C 2H pk a = 5 E) CF 3C 2H pk a = Which is the strongest acid? A) CH 3CH 2H B) CH 3C 2H C) HC"CH D) CH 2=CH 2 E) CH 3CH Which is the strongest acid? A) CH 2ClCH 2CH 2CH 2CH 2C 2H B) CH 3CHBrCH 2CH 2CH 2C 2H C) CH 3CH 2CH 2CBr 2CH 2C 2H D) CH 3CH 2CH 2CHFCH 2C 2H E) CH 3CH 2CH 2CF 2CH 2C 2H 59. Which is the strongest acid? A) CH 3CH 2CH 2CH 2CHFC 2H B) CH 3CHBrCH 2CH 2CH 2C 2H C) CH 3CH 2CH 2CHClCH 2C 2H D) CH 3CH 2CH 2CHFCH 2C 2H E) CH 3CH 2CH 2CHICH 2C 2H 11 12

7 Topic: Relative acid-base strengths 60. Which is the weakest acid? A) CH 3CH 2CH 2CH 2CHFC 2H B) CH 3CHCH 2CH 2CH 2CH 2H C) CH 3CH 2CH 2CH 2CH 2S 3H D) CH 3CH 2CH 2CH 2CH=CH 2 E) CH 3CH 2CH 2CH 2NH 2 Topic: Relative acid-base strengths 64. Select the strongest base. A) H B) RC"C C) NH 2 D) CH 2=CH E) CH 3CH Which of the following substances has a hydrogen atom with pka 25? A) CH 3CH 2CH 2CH 2C 2H B) CH 3CHCH 2C CCH 3 C) CH 3CH 2CH 2C CH D) CH 3CH 2CH 2CH 2CH=CH 2 E) CH 3CH 2CH 2CH 2NH Hydrogen atom(s) from which position(s) is (are) most likely to be abstracted when the following substance is treated with NaH? A) 1 B) 1, 5, 6 C) 1, 2 D) 3, 4, 7, 8, 9, 10 E) Hydrogens from all of the positions are equally likely to be abstracted by NaH. 63. Which of the following correctly lists the compounds in order of decreasing acidity? A) H 2 > HC"CH > NH 3 > CH 3CH 3 B) HC"CH > H 2 > NH 3 > CH 3CH 3 C) CH 3CH 3 > HC"CH > NH 3 > H 2 D) CH 3CH 3 > HC"CH > H 2 > NH 3 E) H 2 > NH 3 > HC"CH > CH 3CH A group of acids arranged in order of decreasing acidity is: HN 3 > CH 3CH > C 6H 5H > H 2 > HC"CH What is the arrangement of the conjugate bases of these compounds in decreasing order of basicity? A) N 3 > CH 3C > C 6H 5 > H > HC"C B) CH 3C > C 6H 5 > N 3 > H > HC"C C) C 6H 5 > N 3 > HC"C > H > CH 3C D) HC"C > H > C 6H 5 > CH 3C > N 3 E) No prediction of relative base strength is possible. 66. What prediction can be made of the relative strengths of the conjugate bases of: H 2S, HCl, SiH 4, PH 3? A) PH 2 > SiH 3 > HS > Cl B) SiH 3 > PH 2 > HS > Cl C) Cl > HS > PH 2 > SiH 3 D) HS > Cl > SiH 3 > PH 2 E) Cl > PH 2 > SiH 3 > HS Topic: Acids/bases- general 67. Which of these species is not amphoteric? A) HC"C B) HS C) NH 3 D) CH 3 E) HP

8 Topic: Acids/bases- general 68. Which of these phosphorus-based acids is dibasic? A) H P H SHRT-ANSWER QUESTINS WITH ANSWERS N PAGES 19-20: 72. Addition reactions are characteristic of compounds with. B) C) D) E) H H P H H H P H H H P P H H H H P P H H H 73. The four basic types of reactions are:. 74. The process of bond-breaking where each fragment takes away one of the electrons from the bond is called. 75. Heterolytic bond-breaking produces. 76. According to Bronsted-Lowry theory, an acid is a substance that can. 77. According to Lewis theory, a base is a substance that can. 78. The molecule or ion that is formed when an acid loses its proton is called the. 69. Why cannot one determine the relative acid strengths of HCl 4 and HN 3 using aqueous solutions of these acids? A) The acids are insufficiently soluble for the measurements. B) A more basic solvent than H 2 must be used. C) H 2 is too basic a solvent for the distinction to be made. D) These oxidizing acids cause redox reactions to occur. E) Actually, the acid strengths can be determined using aqueous solutions. 79. Reagents that seek to react with a proton or some other electron-deficient center are called. 80. A substance that can donate a lone pair of electrons is a according to theory. 70. Which of these is not a diprotic acid? A) H 2S B) H 2S 4 C) H 2 D) (CH) 2 E) H 2P When drawing mechanisms, chemists generally use curved arrows. The curved arrow begins with and points toward. 82. Why do water-insoluble carboxylic acids dissolve in aqueous sodium hydroxide? 83. Bond polarization that takes place through space and through the bonds of the molecule is called the. 84. What are the two fundamental types of energy? 15 16

9 85. Define a protic solvent. 86. Briefly, but clearly, explain why the H hydrogen in acetic acid (CH 3C 2H) is more acidic than in ethanol (C 2H 5H). 87. Isotope labeling is an important tool in the study of reaction mechanisms. How will you selectively deuterate the specified hydrogen atom, indicated by an arrow, in the following compound? Use equations to clarify your answer and briefly explain your rationale. H Topic: Acid-base reactions 88. Write an equation to show the reaction between ethanol, C 2H 5H and methyllithium, CH 3Li. Draw all non-bonding electrons and show electron flow with curved arrows. Topic: Acid-base reactions, solvent selection 89. You are planning to carry out a reaction between propyne, CH 3C CH and sodium amide, NaNH 2. You also need to choose an appropriate solvent for carrying out the reaction. Would ethanol be suitable for this purpose? Explain your rationale clearly. 90. You are planning to purify an impure sample of benzoic acid, known to be contaminated with naphthalene. Propose a strategy for purifying this sample, making use of acid-base principles, using equations to further clarify your answer. ANSWERS MULTPLE CHICE QUESTINS Chapt.3 Svar - Part 3: Syror och baser Fråga Svar Rätt/Fel Fråga Svar Rätt/Fel 1 B 37 D 2 D 38 D 3 E 39 E 4 C 40 C 5 B 41 B 6 B 42 D 7 D 43 C 8 C 44 D 9 E 45 C 10 C 46 C 11 E 47 A 12 C 48 D 13 A 49 B 14 A 50 C 15 B 51 E 16 C 52 E 17 A 53 A 18 E 54 A 19 B 55 C 20 B 56 E 21 E 57 B 22 C 58 E 23 A 59 A 24 E 60 A 25 B 61 C 26 A 62 A 27 E 63 A 28 C 64 E 29 E 65 D 30 B 66 B 31 A 67 D 32 A 68 B 33 A 69 C 34 A 70 C 35 B 71 E 36 D 17 18

10 SHRT-ANSWER QUESTINS ANSWERS: 72. Ans: multiple bonds 73. Ans: substitution, addition, elimination, rearrangement 74. Ans: homolysis 75. Ans: charged fragments/ions 76. Ans: donate a proton 77. Ans: donate a lone pair of electrons 78. Ans: conjugate base 79. Ans: nucleophiles 80. Ans: base; Lewis 81. Ans: a lone pair or covalent bond; a site of electron deficiency 82 Ans: Because they are converted to water-soluble salts. 83 Ans: inductive effect 84. Ans: potential energy and kinetic energy 85. Ans: one that has a hydrogen atom attached to a strongly electronegative element such as oxygen 86. Ans: The greater acidity of the H hydrogen in acetic acid is due primarily to two factors: resonance and inductive effects. In acetic acid, the presence of the neighboring carbonyl group has an electron-withdrawing inductive effect on the H hydrogen, increasing its acidity relative to ethanol, in which there is no carbonyl group. Also, comparison of the respective conjugate bases shows that, unlike the ethoxide ion, the acetate ion is stabilized by resonance. This too, is reflected in the greater acid strength of the corresponding acid species. H H (- H + ) Inductive effect: electron withdrawing (- H + ) resonance stabilized anion 87. Ans: The specified hydrogen is attached to an sp-hybridized carbon and is thus more acidic than all the other hydrogens in the molecule. By using an appropriate strong base, such as NaH or NaNH 2, the acetylenic hydrogen is selectively removed; adding D 2 then replaces the lost hydrogen atom with a deuterium atom. H D i) NaH or NaNH Ans:.. H +.. ii) D 2 : CH 3 Li +.. : Li + + CH Ans: No, ethanol would be unsuitable for carrying out the reaction between propyne and methyllithium. The pka of ethanol is ~16, and sodium amide is strong enough a base to readily abstract a proton from the solvent ( pka of NH 3 is ~38); in doing so, it becomes deactivated and is no longer available to react with propyne (pka ~25). Typically, the selected solvent should be chemically inert toward all substances used in the reaction, so that it does not interfere with the desired reaction. 90. Ans: Benzoic acid reacts with aqueous NaH to form a water soluble salt, while naphthalene, which is not soluble in water to any appreciable extent, does not react with NaH. So, upon shaking the impure sample with NaH (aq), the naphthalene remains as a solid, while the benzoic acid dissolves in the aqueous medium as sodium benzoate. After filtration, HCl is added to the filtrate to regenerate benzoic acid, which precipitates as almost pure crystals. Cooling maximizes the yield of the purified product, after which pure crystals can be obtained by filtration. Alternatively, before beginning the reaction with aqueous NaH, the impure sample is first dissolved in diethyl ether (benzoic acid and naphthalene are both soluble in ether) and placed in a separatory funnel. After shaking thoroughly with aqueous NaH, the aqueous layer (which now contains sodium benzoate) is collected. The rest of the procedure is as described earlier. H water insoluble H water insoluble NaH NaH X Na water soluble No reaction HCl H water insoluble PURE 19 20