Interrogative Pronoun:

We often find ourselves in a situation when we know that a noun has done certain action, but that noun is unknown to us. To learn about this unknown noun, we need to ask questions.

Now, we know that in English, to form a sentence, we need a subject. And only a noun or a pronoun can be the subject of a sentence. But, in our case, the noun is unknown, so how will we form a sentence? Here, interrogative pronouns come to our rescue. We use a suitable interrogative pronoun as the subject.

Interrogative pronouns are pronouns used for making questions about an unknown noun. They replace that unknown noun in the sentence and thus form a question.

In English, there are five interrogative pronouns: Who, Whom, Which, What and Whose.

Let us learn where and when are they used with some examples. Also understand that we use mostly use interrogative adjectives rather than interrogative pronouns in spoken. Thus, some usage of interrogative pronouns might appear absurd in first look.

WHO:

This pronoun is used to interrogate about people and sometimes about animals (when their name is known). ‘Who’ is used in subjective case. This means, ‘Who’ is always used as a subject in a sentence. Also, it can be used for both singular and plural nouns

Examples:

Who wants to sign up for this camp?
Who can take the responsibility of reminding me about this project tomorrow?
Please tell me who took the book out of my shelf.
The Doctor asked who brought the medicines for him?

WHOM:

‘Whom’ is used for people. It can be used for both singular and plural nouns (either for a single person or many people). And it replaces nouns in objective case only. Hence, it can only become the object of a sentence. There is usually confusion between ‘who’ and ‘whom’. It is better to remember that ‘who’ is for the subjective case and ‘whom’ is for the objective case.

Examples:

Whom did you call for help?
To whom should I talk regarding this matter?
Whom should she trust?
Whom are you looking at?

WHICH:

‘Which’ can be used to interrogate about any noun (person or thing or information). It is used in case of selection or choice from given options or from a limited range. It usually becomes quite clear from the context of the sentence that the speaker is providing limited options to select from.

Examples:

Which is your friend in the crowd?
Which is your book in the stack?
We have a wide variety of flavours, which would you like to try?
Which is your car?

WHAT:

‘What’ is used for things or information. When we want to ask some information or interrogate about a thing, we use this interrogative pronoun.

Examples:

What is this place called?
What are you doing?
Can you tell me what these trees are called?
What you have inside your pocket?

WHOSE:

‘Whose’ indicates a possessive case. So, it is used to interrogate about the owner of any possession. It is used for persons and things, both singular and plural. It is used when we want to know to whom something belongs.

Examples:

Whose are these folders?
She wants to know whose is it?
Whose is this bicycle that you are riding?
Whose is the health not good? (It might appear absurd, but it is grammatically correct.)

Ø Interrogative Pronouns vs Interrogative Adjectives→

Do not confuse between interrogative pronouns and interrogative determiners (interrogative adjectives). Which, What and Whose are both interrogative pronouns and interrogative adjectives. So now the question is when they are pronouns and when adjectives. This is a quite confusing question to answer in grammar.

To answer this question, we must know the properties of both pronouns and adjectives.

Pronouns are known to replace nouns to reduce repetition. Thus, they take the position of a noun in a sentence. Pronouns are usually either subject or object in a sentence. In contrast, adjectives are known to modify or qualify nouns. They are positioned just before the noun they modify. They follow the structure ‘adjective + noun’. Now let us look at some examples:

Examples:

As Pronoun	As Adjective
Which are the places you visited this summer?	Which places did you visit this summer?
Which is the song you like the most?	Which song do you like the most?
What is this flavor called?	What flavor is this?
What is your score in this test?	What scores did you get in this test?
Whose is this trophy in your hand?	Whose trophy is this in your hand?
Whose was that voice?	Whose voice was that?

Ø Interrogative Pronouns vs Interrogative Adverbs→

All Wh- words are interrogative words, but not all Wh- words are interrogative pronouns. Some of the Wh- words are interrogative adverbs.

Thus, it is essential for us to learn to differentiate between them. As we know, pronouns replace nouns to reduce repetition. So, an interrogative sentence with an interrogative pronoun gives a ‘noun’ as an answer. But when an interrogative sentence has an interrogative adverb, the answer that we get is an ‘adverb or an adverbial phrase’.

When, Why, Where and How are interrogative adverbs. Let us understand this with some examples.

Examples:

What is the name of the restaurant that you are looking for?

(the answer to the above question will be the name of the restaurant, say ‘Red Robins’, which is a noun)

Where did you go last evening?

(the answer to this question will be an adverb or adverbial phrase, say ‘to the karate class’ )

Who cooked dinner for you?

(the answer to the above question will be the name or relation of the person who cooked the food, say ‘Mother’ which is a noun)

Why are you crying?

(the answer to this question will be an adverb or adverbial phrase, say ‘because she lost her favourite toy’)

Which chocolate would you like to buy?

(the answer to the above question will be the name of the chocolate, say ‘Cadbury’, which is a noun)

When did she visit you last?

(the answer to this question will be an adverb or adverbial phrase, say ‘two months back’)

#KEY-NOTES:

Interrogative pronouns are pronouns used for making questions about an unknown noun
There are five interrogative pronouns: Who, Whom, Which, What and Whose.
Do not confuse between interrogative pronouns and interrogative adjectives.
When, Why, Where and How are interrogative adverbs.