El repel·lent d'insectes és a la motxilla.

Yes. El means the, and Catalan uses definite articles very naturally before nouns.

Here, el repel·lent d'insectes = the insect repellent.

A native English speaker may notice that Catalan often keeps the article in places where English might drop it, but in this sentence it matches English quite closely.

• el = masculine singular the
• la = feminine singular the
• els = masculine plural the
• les = feminine plural the

So El repel·lent... is simply The repellent...

Repel·lent means repellent.

The middle dot in l·l is called the punt volat. It shows that the two l sounds belong to separate syllables, rather than forming the usual ll sound of Catalan.

So:

• ll is normally a special Catalan sound, like the lli in família or millor
• l·l means the two l letters are pronounced separately

This spelling appears in words like:

• col·legi
• il·lusió
• repel·lent

It is a normal part of Catalan spelling, not optional punctuation.

Because de often contracts to d' before a vowel sound.

So:

• de + insectes → d'insectes

This is very common in Catalan and works much like elision in other Romance languages.

A few similar examples:

• d'aigua = of water
• d'estiu = of summer
• d'animals = of animals

So repel·lent d'insectes literally means repellent of insects, which is the normal Catalan way to say insect repellent.

Catalan commonly uses the plural here: repel·lent d'insectes.

Literally, that is repellent for/of insects. Even though English often uses a singular noun as a modifier (insect repellent), Catalan does not build it in the same way. Instead, it uses:

• noun + de
  • noun

So:

• repel·lent d'insectes = insect repellent
• not usually repel·lent insecte

This is a very common difference between English and Catalan word-building.

És is the third person singular form of the verb ser (to be).

So:

• és = is

In the sentence:

• El repel·lent d'insectes és a la motxilla.
• The insect repellent is in the backpack.

A very important spelling point: és has an accent.

• és = is
• es = a pronoun, often meaning something like oneself / each other / itself, depending on context

So the accent matters.

In Catalan, a is often used where English uses in, at, or to, depending on context.

Here:

• és a la motxilla = is in the backpack

Catalan often uses a for location, especially in simple sentences about where something is.

So even though a often translates as to or at, in this sentence it is best understood as in.

This is something learners usually need to get used to: prepositions do not match one-for-one across languages.

Because Catalan normally uses the definite article with the noun here:

• la motxilla = the backpack

So:

• a la motxilla = in the backpack

The noun motxilla is feminine, which is why it takes la.

Compare:

• el sac = the bag
• la motxilla = the backpack

Catalan uses articles very regularly, so including la here is completely normal.

You usually learn the noun together with its article:

• la motxilla

That tells you it is feminine.

There are some patterns in Catalan noun gender, but they are not always perfectly predictable, so it is best to memorize nouns with their article.

For example:

• la motxilla = the backpack
• la bossa = the bag
• el repel·lent = the repellent

In this sentence, the article gives you the gender directly:

• la motxilla → feminine singular

This is the normal, neutral word order:

• El repel·lent d'insectes = subject
• és = verb
• a la motxilla = location

So the structure is basically:

• Subject + verb + place

That is the most natural order for a simple statement.

Catalan can change word order for emphasis, but the sentence as given is the straightforward, standard version.

For example, you might also hear emphasis like:

• A la motxilla hi ha el repel·lent d'insectes.

But the original sentence is simpler and very natural for learners.

A careful approximate pronunciation is:

el re-pel-LENT din-SEK-tes es a la mut-SHI-lya

A few notes:

• repel·lent has stress on the last syllable: -lent
• d'insectes flows together, since de becomes d'
• és is pronounced like ess with an open vowel quality depending on accent
• motxilla is pronounced roughly mo-CHI-lla or mo-TSHI-lya, depending on how you approximate it in English

The tx in motxilla is like the ch sound in chair.

You might hear structures with hi ha, but they are not exactly the same as this sentence.

• és a la motxilla = is in the backpack
• hi ha ... a la motxilla = there is ... in the backpack

Both can be possible depending on context, but they are used a little differently.

Your original sentence identifies where a known object is:

• The insect repellent is in the backpack.

With hi ha, the sentence sounds more like introducing or mentioning the existence/presence of something:

• There is insect repellent in the backpack.

So El repel·lent d'insectes és a la motxilla is the best choice if you are talking about a specific, known item.