I was using my 74173 (d-type register) today and accidentally attached the vcc pin to ground and the ground pin to 5v. I didn't realize this and turned on the power. A couple seconds after turning it on smoke started to come out of the IC so I turned it off. I touched the IC a couple seconds after turning off the power and it was so hot it burned my finger a little. What I am wondering is what is the best way to check if this IC is fried? I could plug it in and see if it seems like it is behaving normal, but I am afraid that even if it works in my tests it may still have an edge case that it is broken for. Basically I want to know if there is any way to check if the IC is 100% functional still instead of just making sure it still works with the cases you test it.
The chip is dead.
As you said yourself, it got hot enough to burn your finger and also burn the epoxy case (hence smoke), both of which mean it has quite literally fried.
In general, the answer to the question "is there a way to check if an IC with unknown condition is 100% functional?" is simply maybe.
The only way to test an IC is to try it, and if it behaves within the manufacturers specifications, then it is most likely functional - though it is not guaranteed to be.
The only way to be more sure (still not certain though) that you have a functional IC is to buy a new one. A new chip is much more likely to be functional than one of unknown condition.