La cadena pasa junto al pedal.

Because a + el contracts to al in Spanish.

• junto a el pedal would be incorrect as written
• It becomes junto al pedal

This contraction happens whenever the preposition a is followed by the masculine singular article el.

Examples:

• Voy al mercado
• Está al lado del coche

One exception: if el is part of a proper name, the contraction usually does not happen, as in Voy a El Salvador.

Junto a means next to, beside, or close to.

In this sentence, junto al pedal means the chain passes near or beside the pedal.

Very similar expressions are:

• al lado de = next to
• cerca de = near

Junto a often sounds a little more compact and natural in descriptions of position.

Pasa is from pasar, which often means to pass or to go by.

So La cadena pasa junto al pedal describes movement or route:

• the chain passes by the pedal
• the chain runs alongside the pedal

This is different from a verb like estar, which would describe location rather than path or movement.

Compare:

• La cadena está junto al pedal = The chain is next to the pedal
• La cadena pasa junto al pedal = The chain passes next to the pedal

Spanish often uses definite articles more often than English does.

Here, la cadena means the chain. In context, it is probably a specific chain already known from the situation, such as the chain on a bicycle or machine.

Also, cadena is a feminine noun, so it takes:

• la in the singular
• las in the plural

Examples:

• la cadena
• las cadenas

You usually learn noun gender along with the noun itself.

In this sentence:

• cadena is feminine → la cadena
• pedal is masculine → el pedal, which becomes al pedal after a

There is not always a perfect rule, but some endings help:

• nouns ending in -a are often feminine, though not always
• nouns ending in -al are often masculine

A good habit is to memorize nouns with their article:

• la cadena
• el pedal

Yes, that would be grammatical and natural.

• junto al pedal
• al lado del pedal

Both can mean next to the pedal or beside the pedal.

There can be a small nuance:

• junto a can sound slightly more direct or physical
• al lado de is very common and neutral

In many contexts, they are interchangeable.

Yes. Pasa is the third-person singular present tense of pasar.

It matches the subject la cadena, which is singular.

Conjugation in the present:

• yo paso
• tú pasas
• él/ella/usted pasa
• nosotros pasamos
• ustedes/ellos/ellas pasan

Since la cadena is singular, the sentence uses pasa.

If both nouns were plural, you could say:

Las cadenas pasan junto a los pedales.

Notice the changes:

• la → las
• cadena → cadenas
• pasa → pasan
• al pedal cannot stay the same, because a + los does not contract
• so you get junto a los pedales

Important:

• a + el = al
• a + los stays a los

A rough pronunciation guide is:

• junto ≈ HOON-toh in much of Latin America
• al ≈ ahl

Together:

• junto al ≈ HOON-toh ahl

A few helpful points:

• the j in junto is a strong breathy sound, not an English j
• the u is pronounced
• a and l in al are both clearly pronounced, though in fast speech the phrase flows smoothly

Yes. Cadena can have several meanings depending on context, such as:

• a physical chain
• a chain on a bicycle
• a store chain
• a TV network

But in La cadena pasa junto al pedal, the presence of pedal strongly suggests a mechanical or bicycle-related meaning.

So here, learners would most naturally understand cadena as a physical chain.

Because por and junto a do different jobs.

• junto a tells you position: next to / beside
• por often means through, along, by, or via, depending on context

If you said La cadena pasa por el pedal, that could sound like the chain goes through or by means of the pedal, which is probably not the intended idea.

La cadena pasa junto al pedal clearly expresses that the chain passes beside the pedal, not through it.