CHEM 2311 HW1. COMPLETELY FILL THE BOXES IN DARK PENCIL, i.e.:, NOT or or STRUCTURE

Transcription

1 EM 2311 W1 Provide answers to the following multiple choice questions on the Scantron form provided in lecture. Make sure that you put your name and bubble in your GTID # on the answer form. MPLETELY FILL TE BXES IN DARK PENIL, i.e.:, NT or or STRUTURE Question 1 Which of the following statements is not true regarding resonance structures? a. All resonance structures must have the same number of electrons b. Each atom in all of the resonance structures must have a complete shell of valence electrons c. All resonance structures must have the same arrangement of atoms d. All resonance structures must be valid Lewis structures Question 2 Which of the following Newman projections represents 2,4-dimethylpentane? 3 ( 3 ) 2 ( 3 ) 2 ( 3 ) 2 3 ( 3 ) 2 ( 3 ) ( 3 ) 2 Question 3 Which of the following structures represents trans-1,2-dimethylcyclohexane? Question 4 Which of the following is the definition of a meso compound? a. A molecule with stereocenter centers which is chiral b. A molecule with stereocenter centers which is not chiral c. A diastereomer with no stereocenter centers d. A chiral compound with more than one stereocenter center

2 Question 5 Which of the following have the R configuration? N 2 3 ( 3 ) 2 3 a. only 1 b. only 2 c. only 1 and 2 d. 1, 2 and 3 Question 6 What is the relationship between the following pair of structures? l 3 l 3 3 l a. They are enantiomers b. They are diastereomers c. The are constitutional isomers d. They are identical 3 l Question 7 What is the index of hydrogen deficiency (or sum of double bonds and rings ) of a compound with a molecular formula of 6 15 N? a. 0 b. 1 c. 2 d. 3 Question 8 What is the IUPA name of the following compound?,3-dimethylcyclopentene b. 1,4-dimethylcyclopentene c. 2,4-dimethylcyclopentene d. 1,3-dimethyl-5-cyclopentene Question 9 ow many isomers (of all types) are there of alkenes with the formula 6 12? 5 b. 16 c. 17 d. 18

3 MEANISM AND REATIVITY Question 10 Which of the following is the correct order of decreasing basicity (stronger base > weaker base)? a. N 3 > MeN 2 > 2 > F b. MeN 2 > N 3 > Me > 4 c. N 3 > Me 3 N > 2 > Me d. 3 Na > Na > NaMe > NaNMe 2 Question 11 Which of the following is present in the highest concentration upon dissolution of 2 S 4 in water? a. 2 S 4 b. + c. 3 + d. - Question 12 Which of the following statements is not true about sodium hydride, Na? a. it is a solid b. it is an acid c. it is soluble in strong base d. it reacts explosively with water Question 13 Which sets of curved arrows accounts for the protonation of propene with I? I I I I Question 14 What is the value of the equilibrium constant, K eq, for the following reaction? K eq + N 2 + N 3 pk a = 25 pk a = b c. 13 d. 1 / 13 Question 15 Which of the following concepts explains Markovnikov s rule as applied to the addition of to propene? a. the relative stability of carbocations b. the nucleophilicity of bromide anion c. the acidity of d. the Aufbau principle

4 Question 16 What type of reactive intermediate is formed in the reaction of an alkene with to give a bromoalkane? a. carbocation b. carbanion c. radical d. cyclic bromonium ion Question 17 What type of reactive intermediate is formed in the reaction of an alkene with 2 and water to give a bromohydrin? a. carbocation b. carbanion c. radical d. cyclic bromonium ion Question 18 What type of reactive intermediate is formed in the reaction of an alkene with aqueous acid to give an alcohol? a. carbocation b. carbanion c. radical d. carbene Question 19 What type of intermediate s formed in the g 2- catalyzed hydration of an alkyne?? a. an alcohol b. an enol c. a 1,2-diene d. an epoxide Question 20 What type of reactive intermediate is formed in the reaction of 2-methyl-2-hexanol with to give 2-bromo-2- methylhexane? a. an alkoxide b. a tertiary cation c. a tertiary radical d. a tertiary anion Question 21 What type of reactive intermediate is formed in the reaction of tert-butyl alcohol with 2 S 4 to give methylpropene? a. tert-butyl cation b. tert-butyl anion c. tert-butyl radical d. tert-butoxide Question 22 What type of reaction mechanism accounts for the reaction of an alkene with aqueous acid to give an alcohol? a. nucleophilic addition b. electrophilic addition c. radical addition d. elimination Question 23 Which of the following statements related to S N 1 reactions is not true? a. The S N 1 reaction can be described as a heterolytic bond cleavage followed by nucleophilic attack b. arbocations are electrophilic c. The charged carbon atom of a carbocation has an unfilled valence shell d. Nucleohiles are Lewis bases

5 Question 24 What is the equation for the rate of formation of 1-iodobutane from the reaction of 1-chlorobutane (Bul) with NaI? a. Rate = k [Bul] b. Rate = k [Bul][NaI] c. Rate = k [NaI] d. Rate = k [Bul] 2 Question 25 Which of the following alkyl halides undergoes the fastest solvolysis reaction with ethanol, 3 2? a. methyl fluoride b. ethyl bromide c. 2-chloropropane d. tert-butyl bromide Question 26 Which of the following energy diagrams best represents the changes in energy during addition of to an alkene? energy energy energy energy reaction coordinate reaction coordinate reaction coordinate reaction coordinate Question 27 In which of the following solvents would the reaction of 1-bromobutane with sodium azide, NaN 3, proceed the fastest? a. acetic acid b. ethanol c. water d. acetonitrile Question 28 Which of the following represents the transition state of the rate-determining step in the reaction between tert-butyl bromide and methanol?

6 Question 29 Which of the following represents the transition state of the rate-determining step in the reaction between 2-bromopropane and sodium methoxide leading to elimination? REATINS Question 30 2 S 4 Question S 4

7 Question g(ac) NaB 4 Question B Na Question 34 What is the major organic product(s) obtained from the following reaction? 3 : Na a. 3-methyl-1-pentyne b. 3-methyl-2-pentyne c. 1-propene + propyne d. propane + propyne Question 35 S 1. NaEt 2. 3 I S S 3 S 2 3 I 3 4

8 Question a. only 1 b. only 2 c. only 3 d. both 2 and 3 3 Question Question Question s NaS 3 2

9 Question 40 2 hν Question 41 What is the major organic product obtained from the following sequence of reactions? 2, 2 Na, 2 Question NaN methyl-4-nonyne -methyl-4-nonyne c. 2-methyl-3-nonyne d. 3-methyl-4-nonyne Question 43 2mol a. 3,4-dibromohexane b. 3,3-dibromohexane c. (E) 3,4-dibromohexene d. 3,3,4,4-tetrabromohexane

10 Question gs 4 2 S 4 Question Na 3 N 3 (l) Question 46 What is the major organic product obtained from the following sequence of reactions? p-toluenesulfonyl chloride NaN 3 S pyridine a. (±)-2-azidopentane b. (R)-2-azidopentane c. (S)-2-azidopentane d. (S)-2-pentyl tosylate

11 Question 47 What is the major organic product obtained from the following sequence of reactions? Na Lindlar catalyst 2. 2 Question 48 What is the major organic product obtained from the following series of reactions? 2 NaN 2 Ph Lindlar catalyst 3 a. (E)-5-phenyl-2-pentene b. 6-phenyl-1-hexene c. (Z)-6-phenyl-2-hexene d. (E)-6-methyl-3-heptene Question 49 What is the major organic product obtained from the following series of reactions? 3 NaN 2 2 Lindlar catalyst Question 50 Which of the following reactions provides anisole (Ph 3 ) in a high yield? a. phenol + sodium methoxide b. bromobenzene + bromomethane c. sodium phenoxide (PhNa) + bromomethane d. bromobenzene + sodium methoxide