The difference is subtle: 1. "What's special in your new classroom?" focuses on specific things or features inside the classroom, like furniture or equipment. 2. "What's special about your new classroom?" asks about the overall qualities or characteristics of the classroom, including its atmosphere, layout, or uniqueness. The second question is broader in scope.

What’s special in = refers to something actually inside the classroom. Maybe the desks, the chairs, the white board etc What’s special about = overall. It could be something it it, it could be its location etc What’s special in your classroom? I love the new chairs we have, they’re really comfortable What’s special about your classroom? It’s very modern, has bright colours and is situated very close to the toilet block!