Question

Which of the following statements is correct?

	a.	None of these statements are true.
	b.	An initiator promotes the effectiveness of a reaction and is recoverable.
	c.	An initiator is consumed by the reaction.
	d.	An initiator serves to hold a polymer chain in a particular orientation,

Answer 1

Answer is C: An initiator is consumed in by the reaction. This is what differentiates initiators from catalysts.

Certain types of polymerization reactions, such as Chain polymerization reactions require a species that would initiate the polymerization process. The species involved in such an initiation step which results in the start of the polymer chain growth is called an Initiator. They are chemical species that decompose to produce reactive radical species.

2,2-azobisisobutyronitrile is an example of an initiator in the free radical chain polymerization of monomers such as Styrene. In the first step, the initiator is broken down to the active radical species which attacks a styrene monomer to produce its radical form that attacks another styrene molecule which is the propagation step. The chain transfer and growth occurs and the reaction is terminated by the addition of two growing chains to form a non-radical species