Question 1

Which of the following statements best describes homolytic bond cleavage in free radical reactions?

Accepted Answer

It produces two radicals, each atom taking one electron from the bond.

Question 2

In the chlorination of methane under UV light, what is the role of $$hv ($$light)?

Accepted Answer

It provides energy for the homolytic cleavage of the Cl-Cl bond, generating chlorine radicals.

Question 3

During the radical halogenation of methane, which step regenerates the chlorine radical?

Accepted Answer

Propagation step

Question 4

Which of the following is the correct order of stability for carbon radicals?

Accepted Answer

Primary \u003c Secondary \u003c Tertiary

Question 5

What is the major product of the mono-bromination of butane using $$Br_2$$ and $$hv$$?

Accepted Answer

2-bromobutane

Question 6

Why is bromination of alkanes more selective than chlorination?

Accepted Answer

Bromine radicals are less reactive and favor formation of the most stable carbon radical.

Question 7

Which reagent is commonly used for selective bromination at the allylic position of alkenes?

Accepted Answer

NBS (N-bromosuccinimide) with $$hv$$

Question 8

In radical polymerization, which monomer is used to produce polyethylene?

Accepted Answer

Ethylene ($$CH_2$$=$$CH_2)$$

Question 9

A student exposes cyclohexene to $$Br_2$$ and $$hv. $$What is the major product?

Accepted Answer

Bromine adds to the allylic position to form 3-bromocyclohexene.

Question 10

Which of the following best explains why NBS is preferred over $$Br_2$$ for allylic bromination?

Accepted Answer

NBS provides a low, steady concentration of bromine radicals, minimizing addition to the double bond.

Question 11

Which of the following is a termination step in the radical chlorination of methane?

Accepted Answer

Combination of two methyl radicals to form ethane

Question 12

During the radical bromination of toluene ($$C_6H_5CH_3) $$with $$Br_2$$ and $$hv$$, which position is brominated?

Accepted Answer

Benzylic position (methyl group)

Question 13

Which of the following is a real-world application of radical polymerization?

Accepted Answer

Production of polyethylene for plastic bottles

Question 14

A chemist wants to selectively brominate the allylic position of 1-methylcyclohexene. Which conditions should be used?

Accepted Answer

NBS with $$hv$$

Question 15

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

Accepted Answer

A chlorine radical abstracts a hydrogen atom from methane, forming HCl and a methyl radical.

Question 16

Which of the following is NOT a possible product when methane is exposed to excess $$Cl_2$$ and $$hv$$?

Accepted Answer

Question 17

Which of the following statements about radical initiators is correct?

Accepted Answer

Radical initiators, such as peroxides, decompose to form radicals that start chain reactions.

Question 18

In the radical bromination of cyclohexene with NBS and $$hv$$, which product is formed?

Accepted Answer

Bromine adds to the allylic position to form 3-bromocyclohexene.

Question 19

Which of the following is the correct mechanism for the initiation step in the radical chlorination of methane?

Accepted Answer

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

Ch 6,7,8

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