Question 1

Which of the following best describes the geometry of a carbon-centered radical?

Accepted Answer

It can be either trigonal planar (sp2) or a shallow trigonal pyramid (rapidly inverting sp3).

Question 2

Which arrow notation is used to represent the movement of a single electron in radical mechanisms?

Accepted Answer

Single-barbed (fishhook) arrow

Question 3

Which of the following statements about radical stability is correct?

Accepted Answer

Radicals are stabilized by resonance, and benzylic radicals are more stable than allylic radicals.

Question 4

Which of the following best explains why bromination is more selective than chlorination in radical halogenation?

Accepted Answer

The transition state for bromination resembles the radical intermediate, making the stability of the radical more important (Hammond Postulate).

Question 5

In the radical halogenation of propane, which product is favored and why?

Accepted Answer

2-chloropropane, because secondary radicals are more stable and form faster.

Question 6

Which of the following is a correct description of the initiation step in a radical chain reaction?

Accepted Answer

A non-radical species undergoes homolytic cleavage to form two radicals.

Question 7

Why are ethers particularly susceptible to autooxidation?

Accepted Answer

They form hydroperoxides upon reaction with atmospheric oxygen, which can be explosive.

Question 8

Which of the following best describes the role of BHT (butylated hydroxytoluene) in food preservation?

Accepted Answer

It acts as a radical scavenger, preventing autooxidation of unsaturated fatty acids.

Question 9

Which of the following is true regarding the anti-Markovnikov addition of HBr to alkenes in the presence of peroxides?

Accepted Answer

The Br radical adds to the less substituted carbon, generating the more stable carbon radical intermediate.

Question 10

Which of the following statements about the termination step in a radical chain reaction is correct?

Accepted Answer

Termination occurs when two radicals combine to form a non-radical species.

Question 11

Why is polychlorination difficult to prevent during the chlorination of methane?

Accepted Answer

Methyl chloride is more reactive towards radical halogenation than methane, leading to further substitution.

Question 12

Which of the following best explains why oxygen acts as a radical inhibitor?

Accepted Answer

Oxygen is a diradical and reacts with two other radicals, preventing chain propagation.

Question 13

Which of the following is a correct statement about the selectivity of halogenation reactions?

Accepted Answer

Bromination is more selective than chlorination due to a larger difference in transition state energies.

Question 14

Which of the following is a propagation step in the radical halogenation of methane?

Accepted Answer

$$ \mathrm{Cl}^\cdot + \mathrm{CH}_4 \rightarrow \mathrm{HCl} + \mathrm{CH}_3^\cdot $$

Question 15

Which of the following best describes the net result of the propagation steps in the radical halogenation of methane?

Accepted Answer

$$ \mathrm{CH}_4 + \mathrm{Cl}_2 \rightarrow \mathrm{CH}_3\mathrm{Cl} + \mathrm{HCl} $$

Question 16

Which of the following is a real-world consequence of radical reactions in the atmosphere?

Accepted Answer

Radical reactions involving chlorofluorocarbons (CFCs) lead to ozone depletion.

Question 17

Which of the following statements about radical polymerization is correct?

Accepted Answer

Radical polymerization proceeds through initiation, propagation, and termination steps.

Question 18

In the autooxidation of cumene, what is the product formed when cumene reacts with $$ \mathrm{O}_2 $$?

Accepted Answer

Cumene hydroperoxide

Question 19

Which of the following best explains why halogenation is a useful synthetic tool in organic chemistry?

Accepted Answer

It allows for the functionalization of otherwise unreactive alkanes, enabling further transformations.

Radical Reactions in Organic Chemistry: Mechanisms, Thermodynamics, and Applications

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