Question 1

Which of the following statements best describes the difference between a haloalkane and an alkyl halide?

Accepted Answer

A haloalkane contains a halogen as the main functional group, while an alkyl halide is a simpler molecule with a halogen attached to an alkyl group.

Question 2

Which of the following is the correct general molecular formula for an alkyl halide?

Accepted Answer

$$\mathrm{RX}$$,\ where\ X\ =\ halide$

Question 3

Which of the following methods is NOT a common way to synthesize alkyl halides?

Accepted Answer

Hydration of alkenes

Question 4

In the radical halogenation of methane, what is the initiation step?

Accepted Answer

$$\mathrm{Cl_2$\ \xrightarrow{hv}\ 2Cl\cdot}$$

Question 5

Which of the following best explains why bromination of alkanes is more selective than chlorination?

Accepted Answer

Bromine radicals are less reactive and more selective, favoring the formation of 3° alkyl bromides.

Question 6

Which of the following is the correct rate law for an $$S_N2$$ reaction?

Accepted Answer

$$\mathrm{Rate\ =\ k[RX][Nu^-]}$$

Question 7

Which of the following statements about the stereochemistry of $$S_N2$$ reactions is correct?

Accepted Answer

The stereochemistry at the reaction center is inverted due to backside attack.

Question 8

Which of the following factors favors the $$S_N1$$ mechanism over the $$S_N2$$ mechanism?

Accepted Answer

A tertiary alkyl halide and a weak nucleophile in a polar protic solvent

Question 9

Which of the following is a good leaving group for nucleophilic substitution reactions?

Accepted Answer

$$\mathrm{I^-}$$

Question 10

Which solvent would best promote an $$S_N2$$ reaction?

Accepted Answer

Dimethyl sulfoxide (DMSO)

Question 11

What is the major product when 2-bromopropane reacts with sodium cyanide in acetone?

Accepted Answer

Propyl cyanide ($$\mathrm{CH_3CH(CN)CH_3$})$$

Question 12

Which of the following statements about Grignard reagents is FALSE?

Accepted Answer

Grignard reagents can be prepared in the presence of water.

Question 13

Which of the following best describes the effect of polar protic solvents on nucleophilicity?

Accepted Answer

Polar protic solvents decrease nucleophilicity by solvating the nucleophile.

Question 14

Which of the following is the correct order of reactivity for alkyl halides in the $$S_N2$$ mechanism?

Accepted Answer

Methyl $$\u003e 1$$° $$\u003e 2$$° $$\u003e 3$$°

Question 15

Which of the following is a limitation of Grignard reagents?

Accepted Answer

They cannot be prepared in the presence of weak acids such as water or alcohols.

Question 16

Which of the following factors does NOT favor elimination ($$E1 or$$ $$E2) $$over substitution ($$S_N1 or$$ $$S_N2$$)?

Accepted Answer

Low temperature

Question 17

According to Zaitsev's rule, which product is favored in an $$E1$$ elimination reaction?

Accepted Answer

The more substituted alkene

Question 18

Which of the following best describes the stereochemical outcome of an $$S_N1$$ reaction?

Accepted Answer

Racemization at the stereocenter

Question 19

Which of the following is the correct rate law for an $$E1$$ elimination reaction?

Accepted Answer

$$\mathrm{Rate\ =\ k[RX]}$$

Alkyl Halides: Substitution and Elimination Mechanisms

Study Guide - Practice Questions