d$)$ A conventional free radical polymerisation mechanism progresses through five main processes to produce a linear polymer from a monomer containing a double bond.

i$.$ Briefly describe the five main processes of free radical polymerisation using the polymerisation of ethane $($ethylene$)$ as your example. Reaction mechanisms must be included.

ii$.$ The monomer double bond may have different levels of substitution. Show how the six possible substitution patterns can affect the ability of a monomer to undergo polymerisation and provide the chemical structure of three readily polymerised monomers with different substitution patterns to illustrate your answer.

iii. Azo compounds are often used in a conventional free radical polymerisation. Explain the role of an azo compound and how changes in the structure of the azo compound may have a large effect on the polymerisation.

iv$.$ Explain how an alkanethiol can be used to control conventional free radical polymerisation. Include in your answer the impact of structure and alkyl chain length of the alkanethiol on the final polymer.