09-18 - 9/18/2009 Choose Choose the order that has the...

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Unformatted text preview: 9/18/2009 Choose Choose the order that has the following acids correctly correctly arranged with respect to increasing acidity. pKa = 3.2 H F H -1.74 O H H 0.18 O C F3 C O H pKa = 3.2 -1.74 H O H increasing acidity H 0.18 O C F3 C O H O A H F D H F F3 C C O H H O H H increasing acidity O O O H Which of the above acids is the most acidic? Which of the above acids is the least acidic? B H O H H H F F3 C C E F3 C C O H H F H O H H increasing acidity O increasing acidity O C H O H H F3 C C O HH F F F3 C C O H H O H H H F increasing acidity increasing acidity Which Which of the following species is the weakest weakest base? pKa table pKa table basicity pKa -7 -1.74 16 16 H A Cl H H H O O D H + Cl H+ H O pKa -7 H Cl H H + Cl H+ H O O H 4 B H E H H 3 -1.74 16 16 H H O H H C H H+ O F acidity O H H+ Which is the acid in the following reaction? A H Cl + acid pKa table Which Which is the conjugate base in the following reaction? reaction? A H Cl + acid H O base B H H H O C H+ Cl D H O base B H H H O C H+ Cl D conjugate base basicity conjugate acid basicity pKa -7 -1.74 16 16 H Cl H H H acidity pKa H + Cl H+ H O O H 5 -7 H H Cl H H + Cl H+ H O O H 6 O H -1.74 16 16 H H O H H O H H+ acidity O H H+ 1 9/18/2009 Does H-Cl spontaneously react with water? H- Does acetic acid spontaneously react with water? O O H+ CH3 C O H H Cl + O H H stronger acid stronger base H O H+ Cl basicity CH3 C O H H + O H H H O stronger acid weaker acid weaker base weaker acid pKa -7 -1.74 16 16 H Cl H H H acidity H + Cl H+ H O O H 7 pKa H O H -1.74 H H O H H+ H O H O C = Ac 8 O H H+ 4.76 AcOH H + AcO CH3 Which of the following acid base reactions is written correctly? A. I and II. C. only I B. only II. D. neither I or II. Which of the following acid base reactions is written correctly? A. I and II. C. only I B. only II. D. neither I or II. I H H C C + O H H C C H + O H I H H C C + O H H C C H + O H pKa = 16 pKa = 25 H H C C H + N H pKa = 16 pKa = 25 H H C C H + N H II H H C C +H N H II 9 H H C C +H N H pKa = 38 pKa = 25 pKa = 38 pKa = 25 10 How does the equilibrium constant, Ka, relate to G° = -RTln Ka thermodynamics? Is H + A1 How does the equilibrium constant, Ka, relate to G° = -RTln Ka thermodynamics? Choose the correct statement more or less stable than H + A2 ? A. H A1 is a weak acid. B. H A1 is a strong acid. C. H A1 and H A2 are strong acids. D. H A1 and H A2 are weak acids. unstable H + A1 G° = -RTln Ka H + A1 G° = -RTln Ka G° G° H A1 H A2 G° G° G° = -RTln Ka H + A2 stable 11 H A1 H A2 G° = -RTln Ka H + A2 Reaction Reaction 12 2 9/18/2009 Use Use the curved arrow formalism to show the bond making and bond bond breaking in the following reaction. weak acid O O H + CH3 C O Which Which species behave as acids in the following equilibrium? acetic acid CH3 C O H H + O H H H O pKa = 4.76 pKa = -1.74 H O H H H O H + strong acid hydrochloric + H Cl acid Cl pKa = -7 pKa = -1.74 H + A1 G° = -RTln Ka G° A. and B. and A. 1 and 3 B. 1 and 4 C. 1, C. 1, 2, 3 and 4 D. 1, 3 and 4 D. 1, E. E. 1 F. F. none of of these H A1 H A2 G° = -RTln Ka H + A2 Reaction 13 14 Which Which of the following reactions produce the compounds on the right right as the major products? (1) Can Can we estimate relative pKas from a knowledge of from bonding? bonding? H A1 H + A1 H + A2 -1.74 4.2 H A2 (2) 11 16 pKas H + A1 (3) 19 34 G° H A1 H A2 G° = -RTln Ka G° = -RTln Ka H + A2 A. and B. and A. 1 and 3 B. 1 and 2 C. 1 only D. 1, 2 and 3 E. 2 only C. only D. 1, E. only F. none F. none of these Reaction 16 Choose Choose the order that has the following compounds correctly correctly arranged with respect to increasing acidity. A. D. propane pKa = 51 CH3 H C H C H H H C N H H H C O H + H O H H H O H + CH3 H C H + H H + H O H H Using Using our concepts of bonding is it ever possible to predict the relative relative acidity of acids? O O H + CH3 C O B. E. H O H C. F. electronegativity H + CH3 C H C H H acetic acid CH3 C O H H + O H H H O A Which of these acids would be predicted to be stronger, A or B? O O H + O F H + F C C F O 2.5 ethylamine pKa = 38 H O H H H O H + CH3 H C H N H H O CH3 3.0 trifluoro F C acetic C acid F F H O H H H O B ethanol ethanol pKa = 15.9 CH3 3.5 17 18 electronegativity table 3 9/18/2009 Using our concepts of bonding is it ever possible to predict the relative acidity of acids? O O H + CH3 C O Review: Is H A a strong acid? H A Is H A1 a strong acid? H A no no acetic acid CH3 C O H H + O H H H O Is H A1 a stronger acid than H A? yes H A H A? Is H A2 a strong acid? yes H A Is A a stronger base than A1 ? yes stronger A pKa = 4.76 Which of these acids would be predicted to be stronger, A or B? O O H + O F H + F C C F O Is H A2 more stable than H + A2 ? no more H+A H + A1 HA H A1 H A2 H + A2 19 pKa = 0.23 stronger acid more stable anion weaker base G° trifluoro F C acetic C acid F F H O H H H O B Reaction 20 Review: acetic acid CH3 O C O H + H O H H H O H + CH3 O C O Review: acetic acid CH3 O C O H + H O H H H O H + CH3 O C O pKa = 4.76 O F F C F C O H + H O H H H O H + F O F C C F O pKa = 4.76 O F F C F C O H + H O H H H O H + F O C O O F C C F O trifluoro acetic acid Are these strong acids? no H+A H + A1 HA H A1 H A2 H + A2 pKa = 0.23 trifluoro acetic acid Is this diagram correctly labeled? CH3 pKa = 0.23 yes H+A O H + A1 C F F HA H A1 C F O G° Reaction G° 21 Reaction 22 Choose Choose the order that has the following acids correctly arranged arranged with respect to increasing acidity. Choose the order that has the following acids correctly arranged arranged with respect to increasing acidity. A. A. D. B. E. C. F. A. A. D. B. E. C. F. H Zn O H H O H H N H H N H O H H + H 23 H Zn O H + H H O H H N H H N H + H H O H O H H + H 24 H O H + H + H 4 ...
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This note was uploaded on 12/25/2009 for the course CHE 320 taught by Professor Ff during the Spring '09 term at SUNY Stony Brook.

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