Na którym dziale jest mąka?

Because na here requires the locative case when it means location.

• Base form: który = which
• Locative masculine/neuter singular: którym

Since dział is masculine singular, którym has to match it:

• który dział = which department
• na którym dziale = in/on which department

So którym is there because of both:

1. the preposition na
2. agreement with dziale

For the same reason: na + location usually takes the locative case.

The noun changes like this:

• nominative: dział
• locative: dziale

So:

• dział = department/section
• na dziale = in/on the department/section

This is a very common pattern in Polish:

• w sklepie = in the shop
• na stole = on the table
• na dziale = in/on the department

Literally, it is something like on which department.

Idiomatic English would usually be:

• in which department
• in which section
• sometimes in which aisle depending on context

Polish often uses na with areas or counters in a shop, even where English would prefer in.

Yes, you may hear that too, and it would be understood.

But na którym dziale sounds very natural when talking about a shop section or department. Polish often treats these places as service areas or counters, which is why na is common.

A few possible versions are:

• Na którym dziale jest mąka? = Which department is the flour in?
• W którym dziale jest mąka? = also understandable; similar meaning
• Gdzie jest mąka? = Where is the flour?
• Na którym dziale znajdę mąkę? = Which department can I find flour in?

That last one is especially natural when asking staff.

Jest is the 3rd person singular of być (to be), so here it means is.

In this sentence, it works like English is located / is found:

• Na którym dziale jest mąka? = Which department is the flour in?

Polish often uses jest in location sentences:

• Gdzie jest chleb? = Where is the bread?
• Gdzie jest cukier? = Where is the sugar?

You could also use a different verb for a slightly different feel:

• Na którym dziale znajdę mąkę? = Which department will I find flour in?

Because with jest, mąka is in the nominative case.

• mąka = nominative singular
• mąkę = accusative singular

Compare:

• Gdzie jest mąka? = Where is the flour?
• Znajdę mąkę. = I will find the flour.

So:

• with jest in this kind of sentence -> mąka
• with a verb taking a direct object, like znaleźć / znajdę -> mąkę

It is nominative singular.

The dictionary form is mąka. It is a feminine noun.

Basic forms:

• nominative: mąka
• accusative: mąkę
• genitive: mąki
• locative: mące

In your sentence, mąka is the thing being talked about as existing in a location, so nominative is used.

Because Polish does not have articles like a/an and the.

So mąka can mean:

• flour
• the flour

The exact meaning depends on context.

That is completely normal in Polish:

• Gdzie jest chleb? = Where is the bread?
• To jest sklep. = This is a shop.

English speakers often look for an article, but Polish simply does not use one.

No, Polish word order is fairly flexible, but some orders sound more natural than others.

The most neutral version is:

• Na którym dziale jest mąka?

This starts with the question phrase, which is very natural.

Other word orders are possible, but they may sound marked or less natural:

• Mąka jest na którym dziale? — possible, but it sounds unusual unless you are emphasizing mąka
• Gdzie jest mąka? — simpler and very natural

So yes, word order can move, but the original sentence is a good standard pattern.

A rough guide:

• mąka ≈ MON-ka, but with a nasal vowel
• dziale ≈ roughly JAH-leh with a soft initial sound

A few useful notes:

• ą is a nasal vowel. Before k, it is often pronounced a bit like on/om.
• Polish stress usually falls on the second-to-last syllable, so:
  • MĄ-ka
  • DZIA-le
  • KTÓ-rym

A rough whole-sentence pronunciation:

• na KTOO-rim JAH-leh yest MON-ka

That is only an approximation, but it can help at first.

Not exactly.

• dział = department / section
• alejka = aisle

So in a supermarket:

• Na którym dziale jest mąka? = Which section/department is the flour in?
• W której alejce jest mąka? = Which aisle is the flour in?

If you are asking where a product is more precisely, alejka may be better. If you mean the general category area, dział works well.

It is understandable and natural enough, but many people would use a slightly simpler or more conversational version, such as:

• Gdzie jest mąka? = Where is the flour?
• Na którym dziale znajdę mąkę? = Which department can I find flour in?
• W której alejce jest mąka? = Which aisle is the flour in?

Why might znajdę mąkę sound especially natural?

Because when speaking to staff, people often ask where they can find something, not just where it is.

So your sentence is good, but these are also very useful real-life alternatives.