Learn Italian: Lo scopo per il quale lavoriamo offre un grande vantaggio. - The purpose for which we work offers a big advantage.

Yes, you absolutely can! per cui means the exact same thing ("for which") and is actually much more common in everyday conversation. per il quale is a bit more formal, but it's very useful because the il clearly points back to the masculine singular noun lo scopo.

Why do we use il quale instead of la quale?

The relative pronoun (il quale, la quale, etc.) must match the gender and number of the noun it is replacing. Since it refers back to lo scopo (the purpose), which is masculine and singular, you must use il quale. If the sentence were about la ragione (the reason), it would be per la quale.

Why is it lo scopo and not il scopo?

Just a quick refresher: for masculine singular nouns, you use the article lo instead of il when the word begins with an "s" followed by another consonant (like the s + c in scopo).

Why is grande placed before vantaggio instead of after it?