Question 1

Which of the following statements best describes the difference between a Lewis acid and a Brønsted-Lowry acid?

Accepted Answer

A Lewis acid is an electron pair acceptor, while a Brønsted-Lowry acid is a proton donor.

Question 2

Which of the following molecules is most likely to act as a nucleophile in an $$\mathrm{S_N2}$$ reaction?

Accepted Answer

$$\mathrm{CH_3CH_2O^-}$$

Question 3

Which of the following best explains why staggered conformations of ethane are more stable than eclipsed conformations?

Accepted Answer

Staggered conformations minimize torsional strain due to electron repulsion between C-H bonds.

Question 4

A compound with the molecular formula $$\mathrm{C_4H_{10}} is $$subjected to infrared (IR) spectroscopy. Which functional group would you expect to be absent from its IR spectrum?

Accepted Answer

Alcohol O-H stretch near $$3300\ \mathrm{cm}^{-1}$$

Question 5

Which of the following statements about chirality is correct?

Accepted Answer

A molecule with four different substituents on a tetrahedral carbon is always chiral.

Question 6

Which of the following is the best description of the rate-determining step in an $$\mathrm{S_N1}$$ reaction?

Accepted Answer

The leaving group departs, forming a carbocation intermediate.

Question 7

A student analyzes an unknown compound by $$^1\mathrm{H}$$ NMR and observes a singlet at $$\delta = 2.1$$ ppm integrating for 3 hydrogens. Which functional group is most likely present?

Accepted Answer

A methyl group adjacent to a carbonyl (acetyl group)

Question 8

Which of the following best explains why tertiary alkyl halides favor elimination ($$\mathrm{E2}) $$over substitution ($$\mathrm{S_N2}) $$reactions when treated with a strong base?

Accepted Answer

Tertiary alkyl halides are too sterically hindered for $$\mathrm{S_N2}$$ reactions.

Question 9

Which of the following is the correct IUPAC name for the compound shown below?

$$\mathrm{CH_3CH_2CH(CH_3$)CH_2CH_3}$$

Accepted Answer

3-Methylpentane

Question 10

Which of the following statements about the mechanism of bromination of alkenes is correct?

Accepted Answer

The reaction forms a cyclic bromonium ion intermediate.

Question 11

A compound is found to be optically inactive, but its molecular structure contains a stereocenter. Which of the following best explains this observation?

Accepted Answer

The compound is a meso compound.

Question 12

Which of the following best describes the product of the reaction of 2-bromopropane with sodium ethoxide ($$\mathrm{NaOEt}) in $$ethanol?

Accepted Answer

Propene via $$\mathrm{E2}$$ elimination

Question 13

Which of the following statements about Markovnikov's rule is correct?

Accepted Answer

In the addition of HX to an alkene, the hydrogen attaches to the carbon with more hydrogens.

Question 14

Which of the following is the major product when 1-methylcyclohexene reacts with $$\mathrm{Br_2$} in$$ $$\mathrm{$$CCl_4$$}$$?

Accepted Answer

Trans-1,2-dibromo-1-methylcyclohexane

Question 15

Which of the following best explains why $$\mathrm{(CH_3$)_3COH} ($$tert-butanol) is more acidic than $$\mathrm{(CH_3$)_3CH} ($$neopentane)?

Accepted Answer

The oxygen atom in tert-butanol stabilizes the negative charge after deprotonation.

Question 16

A student is given a sample of an unknown alkyl halide and observes that it reacts rapidly with sodium iodide in acetone, but not with water. Which type of reaction mechanism is most likely?

Accepted Answer

$$\mathrm{S_N2}$$

Question 17

Which of the following is the correct order of increasing acidity for the following compounds: ethanol, acetic acid, and phenol?

Accepted Answer

Ethanol \u003c Phenol \u003c Acetic acid

Question 18

Which of the following best describes the effect of hyperconjugation on the stability of carbocations?

Accepted Answer

Hyperconjugation stabilizes carbocations by delocalizing positive charge over adjacent C-H bonds.

Question 19

Which of the following statements about the $$\mathrm{E2}$$ elimination mechanism is correct?

Accepted Answer

The $$\mathrm{E2}$$ mechanism requires a strong base and anti-coplanar geometry.

CHM 2001 Organic Chemistry 1 – Syllabus and Study Guide Overview

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