Free Radical Substitution

Question 1

Alkanes can undergo free-radical substitution in which

Answer 1

hydrogen atom gets substituted by a halogen (chlorine/bromine)

Question 2

Since alkanes are very unreactive what is needed for the substitution reaction to occur

Answer 2

ultraviolet light (sunlight

Question 3

The free-radical substitution reaction consists of three steps:
In the initiation step, the halogen bond (Cl-Cl or Br-Br) is broken by …………………….

………………………….. called the propagation step

The reaction is terminated when………………..

Answer 3

UV energy to form two radicals

These radicals create further radicals in a chain reaction

two radicals collide with each other in a termination step

Question 4

Alkanes can undergo free-radical substitution in which a hydrogen atom gets substituted by a halogen (chlorine/bromine)
Ultraviolet light (sunlight) is needed for this substitution reaction to occur

Answer 4

The fact that the bromine colour has disappeared only when mixed with an alkane and placed in sunlight suggests that the ultraviolet light is essential for the free radical substitution reaction to take place

Question 5

In the initiation step the

homolytic fission reaction what does it produce

Answer 5

Cl-Cl or Br-Br is broken by energy from the UV light

This produces two radicals in a homolytic fission reaction

Question 6

Homolytic fission

Answer 6

The process of breaking a covalent within a molecule leading to the formation of radicals. Upon bond breaking, each atom receives one electron from the bonding pair and both atoms become radicals

Question 7

what is a radical

Answer 7

A species with an unpaired electron.