Spring 2007 Final

Spring 2007 Final - 1Chemistry 202/252 Lab Evaluation -...

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1 Chemistry 202/252 Lab Evaluation - Friday, April 27, 2007 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 B D A D A B B A D A B D C B B C C D B A C A C D C C C B A A C A B A B 1. When you do the recrystallization of the adduct of diene and maleic anhydride with methanol, you should avoid prolonged boiling because (A) the adduct may undergo a retro-Diels-Alder reaction to form diene and maleic anhydride (B) the adduct may react methanol to form a solvolysis product (C) the adduct may emit CO 2 because of heating (D) none of above 2. The NaCl pellet used for IR should not be washed by which of the following solvents? (A) acetone (B) diethyl ether (C) dichloromethane (D) water 3. What is the purpose of an acid catalyst in a Fischer Esterification reaction? (A) to protonate the carbonyl oxygen of the carboxylic acid, making the carbon more susceptible toward nucleophilic attack by the alcohol (B) to deprotonate the carboxylic acid, making the carbon more susceptible toward nucleophilic attack (C) to help neutralize the reaction (D) to prevent the formation of by-products 4. In the workup in the Grignard reaction, we add water to convert (C 6 H 5 ) 3 COMgBr to triphenylmethanol, followed by the addition of dilute HCl. What is the purpose of adding HCl? (A) as a catalyst to increase the reaction yield (B) to increase the yield of triphenylmethanol (C) to dissolve triphenylmethanol for further purification (D) to dissolve the basic magnesium salts formed along the reaction 5. What type of reaction is the Nitration of Naphthalene classified as? (A) electrophilic aromatic substitution (B) nucleophilic aromatic substitution (C) solvolysis (D) none of the above 6. In Exp 38, the Wittig synthesis of 1,4-diphenyl-1,3-butadiene, sodium hydroxide was added in the reaction to (A) neutralize acid (B) deprotonate the proton next to PPh 3 (C) dissolve trans -cinnamaldehyde (D) be the solvent 7. In the Aldol condensation experiment, what could happen if the ketone and aldehyde had similar reactivities and could both form enolates? (A) more than 2 substitutions could occur on the ketone substrate (B) a mixture of products could result
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Spring 2007 Final - 1Chemistry 202/252 Lab Evaluation -...

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