Final answer:
Distillation is necessary in the cracking of dicyclopentadiene to remove impurities.
Step-by-step explanation:
In the cracking of dicyclopentadiene, distillation is necessary to remove impurities. Distillation is a process used to separate different components based on their boiling points. In this case, distillation is used to separate the cracked product from impurities such as sulfur, nitrogen, and water.