There are some good usage examples or possessive pronouns in this podcast. You will learn how to say something is mine, hers or yours. Learn how to stand by your stuff and shout out that they are yours!
I saw on the net a couple of translations as follows: 1. "I Don't Know!" = La a’ref!; 2. "I Have No Idea." = La adri! I am not sure of the native distinction, as I am just a learner, but when you first asked the question I thought of la adri as something more emphatic like "don't know and can't know" whereas "la arif" is something like "don't know," without any connotation of it being something hard to know. Thanks for the question!