Is the word mobile a pronoun?

No, the Word 'mobile' is an adjective and a noun.

The adjective 'mobile' describes a noun as able to move or be moved easily (a mobile phone, a mobilehome).

The noun 'mobile' is a Word for a decorative structure that is suspended, allowing it to turn freely in the air; a Word for a thing.

A pronoun is a Word that takes the place of a noun in a sentence. The pronoun that takes the place of the noun 'mobile' is it.

Example: The lobby of the station was dominated by a large mobile. The waiting passengers watched it as it slowly moved in the air currents.