No arrastres la silla por el suelo, que hace mucho ruido.

Because this is a negative command addressed to tú. In Spanish, negative commands use the present subjunctive:

• arrastrar → arrastres
• So: No arrastres = Don’t drag

By contrast, arrastra could be:

• the positive tú command: Arrastra la silla = Drag the chair
• or the él/ella/usted present form: he/she drags / you drag (formal)

So No arrastres is the correct form for Don’t drag... when speaking to one person informally.

Spanish often leaves out subject pronouns when they are already clear from the verb form. In No arrastres, the ending -es already tells you it is aimed at tú.

So:

• No arrastres la silla...
• Tú no arrastres la silla...

Both are possible, but the version without tú is more natural unless you want emphasis.

Here, arrastrar means to drag something along a surface, especially in a way that scrapes.

So arrastrar la silla por el suelo means dragging the chair across the floor rather than lifting it.

Depending on context, arrastrar can also mean things like:

• to pull along
• to drag
• sometimes even more figuratively, to drag someone/something into a situation

But in this sentence, it is the literal physical meaning.

Spanish often uses the definite article where English might also use the, especially when talking about a specific object already known in the situation.

So la silla means:

• the chair

It suggests both speaker and listener know which chair is meant, or that the chair is obvious from context.

If you said una silla, it would sound more like:

• a chair
• any chair, not a specific one

Por el suelo here means along/across the floor.

The preposition por is used because it suggests movement along a surface or through an area. The chair is being dragged over the floor.

Compare:

• por el suelo = along/across the floor
• en el suelo = on the floor

So:

• La silla está en el suelo = The chair is on the floor
• Arrastrar la silla por el suelo = To drag the chair across the floor

It can mean both, depending on context.

In this sentence, el suelo means the floor.

Common meanings:

• indoors: floor
• more generally: ground

In Spain, suelo is very common for floor. In some other varieties of Spanish, piso may also be used for floor, but in Spain piso very often means apartment, so suelo is especially clear and natural here.

Here, que introduces the reason for the command, so it works a lot like because or since.

• No arrastres la silla por el suelo, que hace mucho ruido.
• Don’t drag the chair across the floor, because it makes a lot of noise.

This use of que is very common in everyday Spanish, especially after commands or statements, to give an explanation.

You could also say:

• No arrastres la silla por el suelo, porque hace mucho ruido.

That is also correct. But que often sounds a bit more immediate and conversational in this kind of sentence.

Literally, it means it makes a lot of noise.

The expression is:

• hacer ruido = to make noise

So:

• hace ruido = makes noise
• hace mucho ruido = makes a lot of noise

This is a very common Spanish expression. Spanish uses hacer where English uses make:

• Hace demasiado ruido = It makes too much noise
• No hagas ruido = Don’t make noise

Because mucho modifies a noun, while muy modifies an adjective or adverb.

Here, ruido is a noun:

• mucho ruido = a lot of noise

Compare:

• mucho ruido = a lot of noise
• muy ruidoso = very noisy

So:

• hace mucho ruido = correct
• hace muy ruido = not correct

In practical terms, the meaning is because that makes a lot of noise or because it makes a lot of noise.

The understood idea is the action of dragging the chair, or the situation just mentioned. Spanish often leaves this kind of subject implicit when it is obvious from context.

So you do not need to identify a neat one-word subject in English terms every time. The important thing is that hace mucho ruido refers to the dragging of the chair across the floor.

Yes, but only slightly.

• ..., que hace mucho ruido sounds very natural and conversational.
• ..., porque hace mucho ruido is also correct and maybe a little more explicit.

Both mean essentially the same thing here. A learner should understand both, but it is useful to know that Spanish often uses que in speech to add a reason after a pause.

You would change the command form.

Formal singular (usted):

• No arrastre la silla por el suelo, que hace mucho ruido.

Informal plural in Spain (vosotros):

• No arrastréis la silla por el suelo, que hace mucho ruido.

Formal plural (ustedes):

• No arrastren la silla por el suelo, que hace mucho ruido.

The rest of the sentence stays the same; only the command changes.