Question

Difference between interrogative pronoun and interrogative adjective

Answer 1

An interrogative adjective asks a question and describes a noun.
ex. which book is better
here 'which' is an interrogatibe adjective and is describing the noun book

An interrogative pronoun asks a question but stands alone or doesn't describes a noun
ex. what should i buy for christmas
here 'what' is a interrogative pronoun and it is asking a question and here is not any noun

Answer 2

Interrogative Pronoun can stand alone. Interrogative Adjective modifies a noun; therefore, it cannot stand alone.