Question 1

Which of the following statements best explains why alkyl halides are generally polar molecules?

Accepted Answer

Alkyl halides are polar because the halogen atom is highly electronegative, pulling electron density away from the carbon atom.

Question 2

Which of the following correctly ranks the stability of alkyl radicals from most stable to least stable?

Accepted Answer

Tertiary \u003e Secondary \u003e Primary \u003e Methyl

Question 3

During the halogenation of methane with chlorine under UV light, which step involves the formation of chlorine radicals?

Accepted Answer

Initiation

Question 4

Which of the following best describes a homolytic bond cleavage?

Accepted Answer

A bond breaks so that each atom keeps one bonding electron, resulting in two radicals.

Question 5

Why is bromination of alkanes more selective than chlorination?

Accepted Answer

Bromine is less reactive and forms more stable radicals due to its larger atomic size.

Question 6

Which of the following reactions will produce 1-bromobutane as the major product?

Accepted Answer

$$CH_3CH_2CH=CH_2$ + HBr ($$with peroxide)

Question 7

Which of the following is true regarding the radical addition of HBr to alkenes in the presence of peroxide?

Accepted Answer

The reaction follows anti-Markovnikov's rule, adding Br to the less substituted carbon.

Question 8

Which reagent is commonly used to selectively brominate the allylic position of an alkene?

Accepted Answer

N-Bromosuccinimide (NBS)

Question 9

In the radical halogenation of propane with Cl$$_2$$, which product is favored and why?

Accepted Answer

2-chloropropane, because secondary radicals are more stable.

Question 10

Which of the following statements about the stereochemistry of radical halogenation is correct?

Accepted Answer

Radical halogenation can produce racemic mixtures if a chiral center is formed.

Question 11

Which of the following best describes the propagation step in the radical halogenation of alkanes?

Accepted Answer

Radicals react with stable molecules to produce new radicals and products.

Question 12

A student attempts to add HBr to 1-butene in the presence of peroxide and observes the product. Which mechanistic feature is responsible for the observed regioselectivity?

Accepted Answer

Formation of a bromine radical that adds to the less substituted carbon

Question 13

Which of the following is NOT a reason why alkanes are relatively unreactive?

Accepted Answer

Alkanes have weak $$\pi$$ bonds.

Question 14

Which of the following is a correct statement about the termination step in radical halogenation?

Accepted Answer

Termination involves the combination of two radicals to form a stable molecule.

Question 15

Which of the following alkyl halides would have the highest boiling point, assuming similar carbon skeletons?

Accepted Answer

Alkyl iodide

Question 16

Which of the following is true about the radical addition of HBr to alkenes?

Accepted Answer

No carbocation intermediate is formed, so rearrangement does not occur.

Question 17

Which of the following best explains why the presence of peroxide leads to anti-Markovnikov addition in the reaction of HBr with alkenes?

Accepted Answer

Peroxide initiates a radical chain mechanism, causing Br to add to the less substituted carbon.

Question 18

A chemist wants to selectively brominate the allylic position of cyclohexene. Which reagent and conditions should they use?

Accepted Answer

NBS (N-Bromosuccinimide) in the presence of light or heat

Chapter 11: Alkyl Halides – Properties, Radical Reactions, and Stereochemistry

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