An interrogative pronoun is a pronoun which is used to make asking questions easy. There are just five interrogative pronouns. Each one is used to ask a very specific question or indirect question. Some, such as "who" and "whom," refer only to people. Others can be used to refer to objects or people. Once you are familiar with interrogative pronouns, you'll find that it's very easy to use them in a variety of situations.
Interrogative pronouns can also be used as relative pronouns, which may be found in questions or indirect questions. You'll know for certain that a pronoun is classified as an interrogative when it's used in an inquiring way, because interrogative pronouns are found only in question and indirect questions.
The five interrogative pronouns are what, which, who, whom, and whose.
In some cases, interrogative pronouns take on the suffix –ever. A few can also take on the old-fashioned suffix –soever, which is rarely seen in writing these days. For example:
Interrogative pronouns are very easy to remember and use. Memorize them to make things even simpler.
Sentences containing interrogative pronouns are always questions, so they always end with a question mark. In the following examples, interrogative pronouns have been italicized for ease of identification.