Interrogative Pronouns are such as are used in asking questions. They are who, with the objective whom and the possessive whose; what and which.

Who, whom and whose refer to persons only.

What is a neuter pronoun, and refers only to things without sex.

Which refers to both persons and things.

When which and what are used as adjectives, they refer to both persons and things.

Examples.

Who was the first European to come to India?

To whom did you lend that hook?

Whose son are you?

What are you going to be when you grow up?

What is all this noise about?

Which is it to be, fight or be friends?

Which is the house you are going to live in?

When which and what precede nouns, they are Pronominal Adjectives.

Examples.

What name did he give you?

Which train are you going by?

Which kind of bicycle is the best?

Compound Interrogative Pronouns.

Whoever, whichever and whatever are called Compound Interrogative Pronouns. The termination -ever serves to emphasize the pronouns who, which and what.

Examples.

Whoever else would have thought of doing such a thing? 

Whichever of these flowers shall I choose? 

Whatever do you mean by talking like that?

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