mar_10 - 3/12/2010 [H ][ OAc] [HOAc] O H H C H C O H H H C...

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Unformatted text preview: 3/12/2010 [H ][ OAc] [HOAc] O H H C H C O H H H C H O H H C H O O O + H H H C H O C O H H H C H = 10-4.76 O O + H ~1.0 M/L small but H ~ OAc What is the pH of a 1.0 molar solution of acetic acid? A. 0 B. 1.0 C. 2.38 D. 4.76 E. >4.76 [H ]2 [ 1.0 ] O H H C H C O H H H C H = 10-4.76 [H ] [H ] = 10-4.76/2 = 10-2.38 O O O + H H H C H O C O H H H C H O + H ~1.0 M/L small but H ~ OAc ~1.0 M/L small but H ~ OAc What is the pH of a 1.0 molar solution of acetic acid? A. 0 B. 1.0 C. 2.38 D. 4.76 E. >4.76 What is the pH of a 1.0 molar solution of acetic acid? A. 0 B. 1.0 C. 2.38 D. 4.76 E. >4.76 [H ][ OAc] [HOAc] O H H C H C O H H H C H = 10-4.76 [H ][ OAc] [HOAc] O = 10-4.76 O O + H H H C H O O H H H C H O + H C What is predominant species present at pH = 7.0? What is predominant species present at pH = 7.0? 1 3/12/2010 Choose the order that has the following acids arranged correctly with respect to increasing acidity. H O HN C H C O H H O H H C H C O H H C H O C N H H O HN H C H C O H H O H H C H C O H H H C H O C N H H i ii iii H O HN H C H C O H H O H H C H C O H H H C H O C N H H i ii iii 2.35 4.75 16 i < ii < iii increasing acidity i < iii < ii increasing acidity ii < i < iii increasing acidity ii < iii < i increasing acidity iii < i < ii increasing acidity iii < ii < i increasing acidity i < ii < iii increasing acidity i < iii < ii increasing acidity ii < i < iii increasing acidity ii < iii < i increasing acidity iii < i < ii increasing acidity iii < ii < i increasing acidity A B C D E F A B C D E F H O HN C H C O H H H H N H C H O C O H Carboxylic acids. How are they prepared? H O HN H C H C O H H O H H C H C O H H H C H O C N H H i ii iii 2.35 4.75 16 i < ii < iii increasing acidity i < iii < ii increasing acidity ii < i < iii increasing acidity ii < iii < i increasing acidity iii < i < ii increasing acidity iii < ii < i increasing acidity A B C D E F Which of the following could be used to prepare phenyl acetic acid? Which of the following could be used to prepare phenyl acetic acid? phenyl acetic acid phenyl acetic acid i Mg Br 1. CO2 2. H3O A. i + ii B. i + iii C. ii + iii D. i E. ii F. iii i Br ii C Br N H3O ii C Br N H3O iii H2CrO4 OH iii H2CrO4 OH 2 3/12/2010 Which of the following could be used to prepare phenyl acetic acid? Carboxylic acids and their derivatives O H H C H C O CH3 H H C H O C N H H ester amide O phenyl acetic acid H C H O C O O H H H C H C O O C C H H H Cl H H C i H Br C H acid chloride C N acid O anhydride ii Br H H C H C N H2CrO4 OH O OH H H C H C S CH3 iii nitrile thioester O H H C H C O CH3 H H C H O C O H O O CH3 H H C H C O H H2 O + H H C H C O + HOCH3 ester acid A. about 1.0 B. much greater than 1.0 C . much less than 1.0 Because the products have about the same stability as the reactants the Keq is about 1. O H H C H C O H How can esters be prepared from alcohols and acids? O + HOCH3 + H 2O H H C H C O H + HOCH3 + H 2O benzene 100% If the Keq ~ 1 how can esters be prepared in high yield (100%) from from alcohols and acids? A. 1 B. 2 C. 3 D. 1 and 2 E. 2 and 3 F. 1 and 3 benzene H2O benzene + H2O 1. Remove the water. 2. Use a transition metal catalyst. 3. Use an enzyme. H2O 3 3/12/2010 Esters can be hydrolyzed to acids under acidic conditions. O H H C H C O H C H O + O H H H H H C H C O H + H O H C Give the structure of the first reasonable intermediate of the reaction mechanism. O H H C H C O H C H H + O H O H H H H C H C O H + H O H C H H H H H H How can this equilibrium be adjusted to favor the carboxylic acid? H H C H O C H H C H H O 1. Add excess water. 2. Use a transition metal catalyst. 3. Use an enzyme. O H O H H H H C H C O H H C H H O H H C H C H H C H H O A B C This equilibrium is catalyzed by acid. Give the structure of the 2nd reasonable intermediate of the reaction mechanism. O H H C H C O H C H H + O H O H H H H C H C O H + H O H C H H This equilibrium is catalyzed by acid. Give the structure of the 3rd reasonable intermediate of the reaction mechanism. O H H C H C O H C H H + O H O H H H H C H C O H + H O H C H H O H H C H C H H C H H H H C H H H C O C O H O H H C H H H H C H O C H H C H H H H C H H O C O H O H H C H H H H C H O C O H O H H H C H H H H H C H O C H H O O O H H H C H O C O H O H H H H H C H C O O H H C H C O H H C H H H H C H C O H H C H O C O H O H H C H H H H H C H O C O H O H H C H H A B C A B C What are the products of this reaction? O R C O R1 + O H R O C O + HO R1 H R O C O H O R C O R1 O H R O C O H + O R1 4 3/12/2010 What are the products of this reaction? O OH Why is the sodium carboxylate soluble in water whereas the carboxylic acid it insoluble in water? carboxylic acid alcohol salt 1. ether 2. H Cl O H2O A H2O O Na 1. ether 2. H Cl ether A ether B B O OH Where is the carboxylic acid? Where is the alcohol? O O O O O + O O O H solution O H 12 solid O 12 O O H O O O H O O + HO Na OH OH O O O a solution ? O Na O nutmeg trimyristin a soap! myristic acid a solid H2O clean cat dirty cat O O O O O O O O H + HO Na OH OH O a solution NaCl! O Na a solid O How was solid soap obtained from the solution? A. A. The water was allowed to evaporate. B. The solution was cooled and the soap precipatated. C. An organic solvent was added to the solution. D. Salt was added to the solution. 5 ...
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