Answer: AIBN is good radical initiator
Explanation:
A radical in organic chemistry refers to any specie having a single unshared electron. An initiator is any specie capable of producing radicals thus starting up a chain reaction. Azobisisobutyronitrile is a good initiator basically owing to its structure. It forms radicals by breaking up to release nitrogen gas as shown in the image attached. The two radicals formed both contain the -CN group which stabilizes the radical.
