Voy a pasar por la farmacia antes de volver a casa.

Voy a + infinitive is a very common way to talk about a near future or an intended action in Spanish, much like I’m going to... in English.

So:

• Voy a pasar por la farmacia = I’m going to stop by the pharmacy
• Pasaré por la farmacia = I will stop by the pharmacy

Both are correct, but voy a + infinitive often sounds a bit more immediate, conversational, and natural in everyday speech.

In this sentence, pasar por means to stop by, to drop by, or to go via / pass by a place.

So pasar por la farmacia means the speaker will go to the pharmacy briefly as part of their route or plans.

This is different from the basic verb pasar, which can also mean things like:

• to pass
• to happen
• to spend time

Here, the preposition por is essential to get the meaning stop by / go by.

Because pasar por is the fixed expression used here.

• pasar por la farmacia = to stop by the pharmacy / go by the pharmacy
• ir a la farmacia = to go to the pharmacy

So if you say:

• Voy a la farmacia → you are simply going there
• Voy a pasar por la farmacia → you are stopping there on the way, or briefly including it in your route

The choice of por comes from the verb phrase pasar por, not from a general rule about movement.

Spanish often uses the definite article more than English does.

So la farmacia is normal even where English might just say the pharmacy or sometimes even pharmacy depending on context.

In Spanish, with places like shops, services, and public places, the article is usually included:

• la farmacia
• el banco
• la tienda
• el médico

So pasar por la farmacia sounds natural and standard.

Because antes de is the structure used before an infinitive.

• antes de + infinitive = before doing something

So:

• antes de volver = before returning / before going back

Compare:

• antes de salir = before leaving
• antes de comer = before eating

If a full clause follows, then Spanish usually uses antes de que + subjunctive:

• antes de que vuelva = before I/he/she return(s)

But here the subject is the same and the sentence uses an infinitive, so antes de volver is correct.

Because a casa is the normal expression for home in Spanish when talking about going or returning home.

So:

• volver a casa = to return home
• ir a casa = to go home
• llegar a casa = to arrive home

Using la casa usually refers more literally to the house/building, not the idea of home.

So:

• volver a casa = return home
• volver a la casa = return to the house

The second one is possible, but it sounds more physical and specific.

Yes. Volver can often be translated as:

• to return
• to come back
• to go back

The best English translation depends on context.

In antes de volver a casa, natural English could be:

• before returning home
• before going back home
• before coming back home

All are possible, though returning home or going back home may fit best in a neutral explanation.

Because Spanish often leaves out subject pronouns when the verb ending already shows who the subject is.

• Voy clearly means I go / I’m going
• So yo is unnecessary unless you want emphasis or contrast

For example:

• Voy a pasar por la farmacia = normal, natural
• Yo voy a pasar por la farmacia = adds emphasis, like I’m the one who is going to stop by the pharmacy

This is very common in Spanish.

Often, yes. In many contexts, pasar por suggests a quick or practical stop, not a long stay.

So Voy a pasar por la farmacia often implies:

• I’ll stop by the pharmacy
• I’ll pop into the pharmacy
• I’ll go by the pharmacy for a moment

But the exact length is not stated directly. The context decides how brief it really is.

Yes, that is grammatically correct, but it means something slightly different in feel.

• Voy a pasar por la farmacia = I’m going to stop by the pharmacy
• Voy a ir a la farmacia = I’m going to go to the pharmacy

The second version is more direct and simply focuses on the destination. The original sentence with pasar por can sound more like the pharmacy is a stop along the way or part of a larger plan.

Its position is flexible, though some placements sound more natural than others.

The original is very natural:

• Voy a pasar por la farmacia antes de volver a casa.

You could also say:

• Antes de volver a casa, voy a pasar por la farmacia.

That version gives more emphasis to the timing.

Both are correct. Spanish often allows this kind of movement of time expressions.

Yes, it sounds very natural in everyday spoken Spanish in Spain.

A speaker in Spain would easily say:

• Voy a pasar por la farmacia antes de volver a casa.

It is neutral, normal, and idiomatic. Nothing in it sounds overly formal or unnatural. It is the kind of sentence you could hear in an ordinary conversation about errands or daily plans.