What is an interrogative determiner?

A question word that stands in front of a noun: which kiln, what time, whose docket. It asks the listener to pick, name, or identify that noun. The rest of the sentence follows ordinary question order: Which kiln do you want? The noun stays in the question, which is how you tell a determiner from a pronoun (Which do you want?).

When do I use which and when what before a noun?

Which when the options form a set you can point at or have already named: Which kiln do you want? Which of these frames needs repair? What when the identity or type is open: What time does the ferry leave? What colour is the underglaze? Conventional phrases such as what time and what colour keep what even if only a few answers are likely.

How is whose different from who's?

Whose is the possessive determiner (and pronoun): Whose bag is this? Who's is the contraction of who is or who has: Who's got the spare key? Who's the conservator on call? If you cannot expand it to who is or who has, the spelling is whose.

Can I say the which kiln or whose the bag?

No. Which, what, and whose already occupy the central determiner slot, so the, a, and my cannot join them on the same noun. If you need the, use which of the kilns. Whose bag, not whose the bag.

Is which kiln the same as which as a pronoun?

Same word, different job. Which kiln is a determiner plus a noun. Which on its own is a pronoun, and it is only clear when the noun is already in the context: looking at two kilns, Which do you want is enough. If the noun would help the listener, keep it. A separate page on pronouns in questions covers the noun-less forms.

English grammar · Intermediate

Interrogative Determiners: Which, What, and Whose Before a Noun

Written by Eleanor Whitfield, Lead English Curriculum Editor · Reviewed September 2026

Interrogative determiners are the question words which, what, and whose when they stand in front of a noun: which kiln, what time, whose docket. They ask the listener to pick or name something, and they occupy the determiner slot, so you do not also use the, a, or my on that noun. Which implies a limited set, what an open set, and whose a possessor. They are not the same as which, what, and whose used alone as pronouns.

Which kiln do you want to fire tonight?

which plus a noun, asking for one of a known set

What it is

An interrogative determiner sits in front of a noun and turns the noun phrase into a question: Which kiln do you want? What time does the ferry leave? Whose docket is this? The noun stays in the sentence; the determiner is doing the asking. That is the difference from a pronoun question, where which, what, or whose stands alone (Which do you want? What is this? Whose is this?). Because the slot is a determiner slot, the, a, and my cannot join it: not the which kiln, not whose the docket.

Which crate goes on the first ferry? What colour is the glaze? Whose keys are on the hook? (Each question word is followed by a noun; the rest of the question uses ordinary auxiliary-subject order.)

How to spot it

If which, what, or whose is immediately followed by a noun (or adjective + noun) and the sentence is a question, you have an interrogative determiner. If there is no noun after it, you have an interrogative pronoun.

Which platform does the coastal train leave from? (which + noun, limited set of platforms)
What time is the first firing? (what + time, open in form, conventional collocation)
Whose bag was left in the wings? (whose + noun, asking for the possessor)
What sort of glaze is this? (what + sort of + noun, asking for a type)

Which and what also start relative clauses (the kiln which we fired). Those are relative, not interrogative. This page is only the question use before a noun.

Interrogative Determiners Quick Reference

Which, what, and whose in front of a noun

Determiner	Asks for	Example
which + noun	one (or more) of a known set	Which kiln do you want to fire?
what + noun	an open identity, type, or information	What time does the ferry leave?
whose + noun	the possessor of that noun	Whose docket is this?
which + plural noun	one or some of a known group	Which crates go on first?
what + kind/sort/type of	a category	What kind of glaze is that?
what + colour/size/time	a property, often conventional	What colour is the underglaze?
whose + noun, no extra possessive	not whose the / whose my	Whose spare key is this?
determiner vs pronoun	noun present vs noun absent	Which kiln? vs Which?

Common Interrogative Determiners Examples in English

The three determiners in the uses that decide which one you pick:

Which: A Limited Set

Which kiln do you want to fire tonight?: the kilns are already in view or known
Which platform did you say?: a small numbered set
Which of these frames needs repair?: which of + demonstrative, still a closed set
Which way is the side door?: which way: conventional, two or a few directions

Which of + pronoun or noun phrase is common when the set has just been named: which of them, which of the crates.

What: An Open Identity or Type

What time does the first ferry leave?: what time, not which time, as a clock question
What colour is the underglaze?: what + property noun
What size crate do we need?: what size as a premodifier of crate
What news from the quay?: what + uncountable noun, open information

What time, what colour, what size, what sort are so conventional that they stay with what even when the options are in practice few.

Whose: Asking for a Possessor

Whose bag was left in the wings?: whose + noun as the subject of a passive
Whose spare key is on this hook?: whose + noun phrase after is
Whose docket did you sign?: whose + object noun, ordinary did-question
In whose name is the booking?: formal: whose inside a preposition phrase

Whose already means of whom / of which, so you do not add of: not whose of bag, and not who's bag (who's is who is or who has).

Inside a Longer Question

Do you know which kiln they fired last?: embedded: statement order they fired, which + noun kept
Could you tell me what time the ferry leaves?: embedded what time, no does inside
I wonder whose crate this is.: embedded whose, no question mark needed on I wonder
Which crate did she say needed a new label?: which + noun stays at the front of a long question

In an embedded question the inversion disappears, but the determiner still sits in front of its noun.

How Interrogative Determiners Work

One determiner slot, a choice between closed and open sets, and ordinary question order after the noun.

The Determiner Takes the Whole Noun Phrase to the Front

Which, what, and whose cannot be split from the noun they determine. The whole phrase moves to the front of the question: Which kiln do you want, not Kiln which do you want or Which do you want kiln. After that phrase, the rest of the question is the usual auxiliary-subject-verb pattern: Which kiln do you want to fire? What time does the ferry leave? Whose bag did you find?

Which kiln do you want to fire tonight?

which kiln moves as one phrase, then do + you + want

Determiner + noun, then ordinary question order.

Which Is Closed, What Is Open

Which asks the listener to choose from a set you both can identify: the kilns in this room, the platforms on this board, these two frames. What asks the listener to supply an identity or a type from an open range: what time, what colour, what news. In the middle, usage is conventional: what time and what colour stay with what even if only a few answers are likely; which way is fixed with which. When you can point at the options, prefer which.

Which of these two glazes dries faster?

these two makes the set closed, so which

Pointable set: which. Open identity: what.

Whose Fills the Possessive Determiner Slot

Whose is the question form of my, your, her, their and of the possessive 's. It already includes possession, so you do not add a second possessive or an article: Whose spare key, not whose the spare key, not whose's key. Who's is a different word, the contraction of who is or who has: Who's got the spare key is a pronoun question plus have got, not a whose-question.

Whose spare key is on this hook?

whose + noun, no article, not who's

Whose + noun. Who's = who is / who has.

No Second Central Determiner

Which, what, and whose are central determiners. They do not combine with the, a, this, my, or every on the same noun: not the which kiln, not what a time in a genuine question (What a time is an exclamative, a different construction). Quantifiers can sometimes follow which of (which of the crates), because of takes a full noun phrase that has its own determiner.

Which of the crates go on the first ferry?

which of + the crates: of licenses a second determiner

Not the which. Which of the is fine.

Common Mistakes with Interrogative Determiners

Incorrect: The which kiln do you want to fire?

Correct: Which kiln do you want to fire?

Which already fills the determiner slot. The cannot sit in the same slot. Which of the kilns is the way to keep the when you need it, because of introduces a new noun phrase.

Incorrect: Who's bag is this?

Correct: Whose bag is this?

Who's is who is or who has. The possessive determiner before a noun is whose. Expand the contraction: who is bag is this fails, so the spelling must be whose.

Incorrect: What kiln of these two do you want to fire?

Correct: Which of these two kilns do you want to fire?

A closed, pointed-at set takes which, not what. Which of these two kilns keeps of plus a full noun phrase. What kiln is possible only when the set is open (What kiln did they use, when you have no list).

Incorrect: Which do you want kiln?

Correct: Which kiln do you want?

The determiner and its noun move together. Splitting them leaves which as a pronoun and kiln stranded. Either keep which kiln at the front, or drop kiln entirely: Which do you want.

Whose as a Determiner, and What + Kind Of

Two patterns that attract extra words they do not need.

Whose vs. who's

Whose is the possessive determiner (and pronoun). Who's is who is or who has. In a possession question before a noun, only whose is possible. A quick test: expand the contraction. Who's bag is this cannot become who is bag.

Whose bag is this?: whose + noun, possessive question
Who's got the spare key?: who is/has: who's + verb, not a determiner
Who's the conservator on call?: who is, pronoun + complement

In speech they sound the same. In writing the expansion test settles it.

What kind / sort / type of

To ask for a category, English uses what kind of, what sort of, or what type of + noun: What kind of glaze is that? Kind is singular even when you expect a mass or a plural after of (What kind of prints are these is heard, but What kind of print is this is the careful form when one object is in view). Which kind of appears when the kinds have already been listed.

What kind of glaze is that?: open request for a category
What sort of crate do we need?: sort of + noun, same pattern
Which kind of glaze dries faster, the satin or the matt?: which kind of once the kinds are named

What kind of a... with an extra a is informal British (What kind of a mess is this) and is not the default.

What about and what if

What about + noun phrase is a suggestion or a prompt (What about Thursday?), not an interrogative determiner on Thursday. What if + clause is a hypothetical (What if the ferry is cancelled?). Neither puts what in a determiner slot before a noun in the which/what/whose sense.

What about Thursday for the firing?: what about as a suggestion, not what + Thursday as a determiner
What if the kiln is still hot?: what if + clause
What day works for the firing?: true determiner: what + day

If you need a determiner question about a day, use what day or which day, not what about on its own.

Quick Check: Interrogative Determiners

Choose which, what, or whose, and keep the noun next to it.

1. ___ kiln do you want to fire, the spare or the main one?

Answer: Which

closed set of two, so which

2. ___ time does the first ferry leave?

Answer: What

what time is the conventional open clock question

3. ___ bag was left in the wings?

Answer: Whose

asking for a possessor, whose + noun

4. Fix: Who's docket is this?

Answer: Whose docket is this?

whose, not who's

5. Embedded: Could you tell me ___ platform the coastal train leaves from?

Answer: which

platforms are a known numbered set; statement order after the noun

Interrogative Determiners FAQs

What is an interrogative determiner?: A question word that stands in front of a noun: which kiln, what time, whose docket. It asks the listener to pick, name, or identify that noun. The rest of the sentence follows ordinary question order: Which kiln do you want? The noun stays in the question, which is how you tell a determiner from a pronoun (Which do you want?).
When do I use which and when what before a noun?: Which when the options form a set you can point at or have already named: Which kiln do you want? Which of these frames needs repair? What when the identity or type is open: What time does the ferry leave? What colour is the underglaze? Conventional phrases such as what time and what colour keep what even if only a few answers are likely.
How is whose different from who's?: Whose is the possessive determiner (and pronoun): Whose bag is this? Who's is the contraction of who is or who has: Who's got the spare key? Who's the conservator on call? If you cannot expand it to who is or who has, the spelling is whose.
Can I say the which kiln or whose the bag?: No. Which, what, and whose already occupy the central determiner slot, so the, a, and my cannot join them on the same noun. If you need the, use which of the kilns. Whose bag, not whose the bag.
Is which kiln the same as which as a pronoun?: Same word, different job. Which kiln is a determiner plus a noun. Which on its own is a pronoun, and it is only clear when the noun is already in the context: looking at two kilns, Which do you want is enough. If the noun would help the listener, keep it. A separate page on pronouns in questions covers the noun-less forms.