When would you be most likely to use an interrogative noun?

It's important to clarify that there's no grammatical category called "interrogative noun." You're likely thinking about interrogative pronouns, which are words used to ask questions.

Here are some examples of interrogative pronouns and when you might use them:

* Who: Used to ask about a person or people.

* Example: Who is coming to the party?

* Whom: Used as the object of a verb or preposition (though its use is declining in modern English).

* Example: Whom did you invite?

* Whose: Used to ask about possession.

* Example: Whose car is that?

* What: Used to ask about a thing or things.

* Example: What did you buy?

* Which: Used to ask for a specific item from a group.

* Example: Which cake would you like?

* Why: Used to ask for a reason.

* Example: Why did you do that?

* When: Used to ask about time.

* Example: When are you leaving?

* Where: Used to ask about a place.

* Example: Where is the library?

* How: Used to ask about a manner or method.

* Example: How did you get here?

You'd use interrogative pronouns whenever you want to ask a question that requires more specific information. They are essential for forming direct questions in English.