Welches Waschmittel benutzt du für die Bettwäsche?

Because Waschmittel is a neuter noun in German: das Waschmittel.

The question word welch- changes its ending to match the noun’s gender, number, and case. Since Waschmittel is neuter singular, you get:

• welches Waschmittel

This is the same pattern as:

• welcher Tisch (masculine)
• welche Lampe (feminine)
• welches Buch (neuter)

In this sentence, welches Waschmittel is the thing being asked about, so it is in the accusative case, but for neuter singular, the form is still welches.

German main clauses usually put the conjugated verb in second position.

In a W-question, the question word or question phrase comes first, and the verb comes second:

• Welches Waschmittel = first position
• benutzt = second position
• du = after the verb

So the structure is:

• Welches Waschmittel benutzt du ... ?

This is the normal German question pattern.

If you said du benutzt welches Waschmittel?, it would sound unusual and not like a standard neutral question.

Yes. du is the informal way to say you, used with friends, family, children, and people you know well.

If you want to be polite or formal, you would use Sie:

• Welches Waschmittel benutzen Sie für die Bettwäsche?

Notice that the verb changes too:

• du benutzt
• Sie benutzen

So the original sentence is simply the informal version.

Because Bettwäsche is a feminine noun:

• die Bettwäsche

Also, the preposition für always takes the accusative case.

So after für, you need the accusative form of the article. For feminine nouns, the accusative article is still die:

• nominative: die Bettwäsche
• accusative: die Bettwäsche

So:

• für die Bettwäsche

is exactly what you would expect.

Bettwäsche usually means bed linen or bedding items made of fabric, especially things like:

• sheets
• pillowcases
• duvet covers

It is often used as a collective singular noun, similar to how English can say bedding or bed linen.

So even though it refers to a set of items, German commonly uses the singular noun:

• die Bettwäsche

Yes, it is singular.

In this sentence, Waschmittel means laundry detergent in a general sense, not necessarily one individual package. German often uses the singular for substances or product types like this.

So:

• Welches Waschmittel benutzt du ... ?

means something like Which detergent do you use ... ? or What detergent do you use ... ?

You could use the plural Waschmittel in other contexts, since the plural form is also Waschmittel, but here the singular makes the most sense.

Because welches is already acting as the determiner.

In English, we say:

• which detergent

not usually which the detergent

German works the same way here:

• welches Waschmittel

The word welches fills the role that an article like das would normally fill. So you do not add another article.

It can feel like either one in English.

German welch- often corresponds to:

• which
• what

depending on context.

So this sentence could naturally be understood as:

• Which detergent do you use for the bed linen?
• What detergent do you use for the bed linen?

English may prefer one or the other depending on the situation, but the German is completely normal.

The dictionary form is benutzen, meaning to use.

In the sentence, benutzt is the 2nd person singular present tense form:

• ich benutze = I use
• du benutzt = you use
• er/sie/es benutzt = he/she/it uses

So benutzt du means do you use or you use, depending on sentence type.

Yes. benutzen and verwenden both mean to use and are often interchangeable.

So you could also say:

• Welches Waschmittel verwendest du für die Bettwäsche?

That would also be correct.

A rough difference is:

• benutzen = very everyday, common
• verwenden = sometimes a little more neutral or slightly more formal

But in this sentence, either verb works well.

Here für means for, showing what the detergent is intended for:

• für die Bettwäsche = for the bed linen

So the sentence is asking which detergent you use for washing bed linen or for that type of laundry.

German often uses für in exactly this kind of practical everyday question:

• Welches Shampoo benutzt du für trockenes Haar?
• Welche Creme benutzt du für deine Hände?

It marks the purpose or target.

Sometimes German can omit articles in very general statements, but in this sentence für die Bettwäsche sounds more natural.

• für die Bettwäsche = for the bed linen / for your bed linen / for that category of laundry

If you say für Bettwäsche, it may sound more label-like or technical, as if you are talking about a product category rather than asking a normal everyday question.

So for a normal conversation, für die Bettwäsche is the safer choice.

It is in the present tense, but like the English present tense, it can describe a habitual action.

So benutzt du can mean:

• do you use
• are you using only in some contexts, but less likely here
• what do you usually use

In this sentence, the most natural interpretation is habitual:

• What detergent do you use for bed linen?
• in other words, What detergent do you normally use?