The difference between "que" and "cual"?
I wonder what is the difference between "que" and "cual"? I know that "cual" should be used after a noun. And when you select one thing from more options, you say "cual", too.
However, why in this sentence we use "que" and not "cual"?:
Se trata del artículo que escribí.
Or, is this sentence correct?:
Es el chico cual encontré ayer.
From the website mentioned in the referenced link from Antonio:
This is the tip that I've found most useful in the past.
Cuál Used Before Forms of Ser
Cuál is used before es and other forms of the verb ser, meaning "to be," when not seeking a definition.
For example, ¿Cuál es tu número de teléfono?, meaning, "What is your phone number?"
Or, ¿Cuál es tu problema?, meaning, "What is your problem?"
Or, ¿Cuáles son las ciudades más grandes?, asking, "What are the biggest cities?"
My guess is that "Es el chico cual encontré ayer." probably should be "Es el chico que encontré ayer." Que is very flexible in Spanish and is often used to mean either what or who/whom in English, but I don't think that you can use cuál for who/whom.