CH 331 Organic Chemistry Practice Exam 2 PDF

**CH 331 Organic Chemistry -- Practice for EXAM 2, Chapters 4-6** **Part A. Choose the best answer.** 1\. Which compound below has a ***meso* f**orm? A. 1,2-dichlorobutane B. 1,3-dichlorobutane **C.** 2,3-dichlorobutane D. 1,4-dichlorobutane 2\. Identify the tertiary alcohol(s). A. only I...

**CH 331 Organic Chemistry -- Practice for EXAM 2, Chapters 4-6** **Part A. Choose the best answer.** 1\. Which compound below has a ***meso* f**orm? A. 1,2-dichlorobutane B. 1,3-dichlorobutane **C.** 2,3-dichlorobutane D. 1,4-dichlorobutane 2\. Identify the tertiary alcohol(s). A. only I B. only II C. only III D. both I and III +-----------------------------------+-----------------------------------+ | 3.  | Arrange the following | | | carbocations in order of their | | | decreasing stabilities (most | | | stable first). | | | | | |   | +-----------------------------------+-----------------------------------+ -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 4\. Give the configurations of carbons 1 and 2, respectively, in the structure shown below. A. R and R B. R and S C. S and S D. S and R +-----------------------------------+-----------------------------------+ | 5.  | Which of the following | | | mechanistically depicts the | | | protonation of *tert*-butyl | | | alcohol by hydrogen bromide?\ | | |  | | | Picture | | | | | |  | | | Picture\ | | |   | +-----------------------------------+-----------------------------------+ 6\. A limitation of substitution reactions with alkyl halides is that a competing elimination reaction often occurs. Consider the reaction below. One of the products results from the substitution reaction, and the other product results from the elimination reaction. What is being removed from the alkyl halide in the elimination reaction?  A. Br B. OCH~3~ C. Br and OCH~3~ D. Br and H 7\. Which of the following molecules are **chiral**? A. only I B. I and III C. II and III D. I, II, and III 8\. How many stereoisomers of **2,4-pentanediol** are possible?  A. 2 B. 3 C. 4 D. 6 9\. What is the relationship between the following two molecules? A. identical B. enantiomers C. diastereomers D. constitutional isomers 10\. How many chirality centers are there in the following molecule?  A. only one B. two C. three D. four 11\. Which of the following statements are **TRUE**? A. I and II B. I and III C. II and III D. I, II, and III 12\. Which sawhorse drawing below has the identical conformation as the following Fischer projection?  13\. Which of the following molecules is(are) chiral? A. only I B. I and II C. II and III D. I, II, and III 14. The most specific description of the relationship between these two molecules is: A. identical B. isomers C. enantiomers D. diastereomers 15\. What are the products of the following reaction? **A.**1-bromobutane and water B.1-bromobutane and hydrogen C.butane and HOBr D. CH~3~CH~2~CH~2~CH~2~OBr + hydrogen 16\. Arrange the following alcohols in order of their decreasing reactivity with HBr (most reactive first).  A. I \> II \> III B. I \> III \> II C. III \> I \> II D. II \> III \> I 17\. Which of the following is most reactive with HBr? A. CH~3~OH B. CH~3~CH~2~OH C. (CH~3~)~2~CHOH D. (CH~3~)~3~COH 18~.~ Identify the functional group in the boxed area. A. ester B. ketone C. carboxylic acid D. ether 19\. Which halogen forms the weakest bond to carbon? A. F B. Cl C. Br D. I 20\. What occurs when an **optically active alcohol reacts with HBr** to give an alkyl halide? A. incomplete and varying inversion of configuration takes place at the chirality center B. complete inversion of configuration takes place at the chirality center C. the chirality center retains its configuration D. the molecule loses its optical activity 21\. Which of the following **carbocation rearrangements** is likely to occur? A. 2° → 2° **B.** 2° → 3° C.3° → 2° D.2° → 1° 22\. Identify the leaving group in the following reaction.  A. B. C. D. 23\. Which of the following undergoes a substitution reaction with sodium cyanide in DMSO at the **fastest rate**? A. CH~3~CH~2~F B. CH~3~CH~2~Cl C. CH~3~CH~2~Br D. CH~3~CH~2~I 24\. Which of the following reacts by the **S~N~2** at the fastest rate? A. CH~3~Br B. CH~3~CH~2~Br C. (CH~3~)~2~CHBr D. (CH~3~)~3~CBr 25\. The species shown below represents the transition state for the A. reaction of 1-propanol with HBr. B. reaction of 1-bromopropane with OH^-^. C. addition of HOBr to 1-propene. D. addition of HBr to propene with peroxides. 26\. Which one of the following correctly describes the reaction below?  27\. The major product(s) of this reaction would be A. only (R) B. only (S) C. \(R) and (S) D. achiral 28\. The major product(s) of this reaction would be  A. only (R) B. only (S) C. \(R) and (S) D. achiral