In general, an noun or an pronoun is located in front of an preposition "of". By the way, I happen upon some sentences including an adjective.
The gallery is full of people.
The society is free of poverty and disease.
In both sentences, both full and free are the adjective
I conceive there is definitely a grammatical reason why these adjective stand between a verb "be" and a preposition "of".
Please, let me know the reason.