This will be a very short article. (Hurray!)
The primary interrogative pronouns are who, whom, whose, which, and what.
As you can see, interrogative pronouns are used to ask questions. (Similar to possessive pronouns, there is a difference between interrogative pronouns and interrogative adjectives. The former replaces the noun; the latter modifies the noun.)
- Who won?
- Whom shall we invite to our party?
- Whose did Nan break?
- Which pays better?
- What is Peter wearing?
Those are all interrogative pronouns. Contrast that to the following interrogative adjectives:
- Whose cup did Nan break? (Whose modifies cup.)
- What shirt is Peter wearing? (What modifies shirt.)
- Which job pays better? (Which modifies job.)
Who is crying over seeing his friends’ bromance on Tumblr?