Question

Question 1 (1 point)
Which one of the following species would NOT
react with free radicals?

Another free radical
Carbon-Carbon double bonds
Carbon-Oxygen bonds
Carbon-Hydrogen bonds

Question 2 (1 point)
What is a requirement for the halogenation of
alkanes through a free radical process?

A catalyst
Heat or light
Water
Oxygen gas

Question 3 (1 point)
Which of the following is NOT part of a radical
reaction mechanism?

Initiation
Termination
Propagation
Extension

Question 4 (1 point)
What is the major product for the free radical
bromination of 2-methyl butane?

1-bromo-2-methyl butane
1-bromo-3-methyl butane
2-bromo-3-methyl butane
2-bromo-2-methyl butane

Question 5 (0.25 points)
Bromination is more selective than chlorination.
True
False

Question 6 (0.25 points)
Free radicals can be stabilized by resonance.
True
False

Question 7 (0.25 points)
Free radical halogenation is a substitution
reaction
True
False

Question 8 (0.25 points)
Polyethylene (PE) can be made from the free
radical polymerization of ethene.
True
False

Answer 1

Which one of the following species would NOT
react with free radicals?

Another free radical
Carbon-Carbon double bonds
Carbon-Oxygen bonds
Carbon-Hydrogen bonds

Free radicals do not react with Carbon-Oxygen bonds as the bond between them is quite strong. Reagents that have higher bond strength proceed via different mechanism and the ones with lower bond strength tend to form radicals when in contact with a free radical

Question 2
What is a requirement for the halogenation of
alkanes through a free radical process?

A catalyst
Heat or light
Water
Oxygen gas

Halogenation of alkane takes place in the presence of UV light or heat equivalent to energy associated with UV light.

Question 3
Which of the following is NOT part of a radical
reaction mechanism?

Initiation
Termination
Propagation
Extension

Extension is not a part of radical mechanism.

Initiation in radical reaction mechanism indicates the formation of first free radicals.

Termination indicates the addition of two radicals to form a molecule

Propagation indicates further addition of free radical with heavier molecule to initiate the chain of addition of radicals

Question 4
What is the major product for the free radical
bromination of 2-methyl butane?

1-bromo-2-methyl butane
1-bromo-3-methyl butane
2-bromo-3-methyl butane
2-bromo-2-methyl butane

Bromine is very regioselective when it attacks 2-methyl butane and the tertiary carbon is the one which is most prone to get attacked. The relative rate of attacks are 1640:82:1 for tertiary:secondary:primary. Thus, when bromine attacks the radical with tertiary carbon, it will tend to form 2-bromo-2-methyl butane.

Question 5
Bromination is more selective than chlorination.
True
False

True. Bromination is more regioselective than chlorination with relative rate of attacks towards tertiary, secondary and primary sites having ratio of 1640:82:1.

Question 6
Free radicals can be stabilized by resonance.
True
False

True. The delocalization of free radicals over several carbons can help them get stabilized. Thus, free radicals can stabilized by resonance.

Question 7
Free radical halogenation is a substitution
reaction
True
False

True. Free radical halogenation is a involves substitution of a chlorine or a bromine atom in place of a hydrogen present in an alkane.

Question 8
Polyethylene (PE) can be made from the free
radical polymerization of ethene.
True
False

True. The chain inititation takes place by production of free radicals some molecules of ethene and the oxygen initiator.