Does clindamycin hcl contain sulfa?

yes

No, they are two separate acitive pharmaceutical ingredients.

No, and here is a picture http://en.wikipedia.org/wiki/File:Trazodone.svg

No. "Sulfa" is short for "sulfamide". Nitrofurantoin is not a sulfamide (in fact, it doesn't have any sulfur in it at all).

Yes, it is a synthetic opioid.