What is the interaction between snakes and pepper spray? Does the spray have the same effect as on humans? Can it be used in a dangerous situation e.g. cornered venomous snake?

Yes, pepper spray will work on most snakes... but if you have a venomous snake cornered, it's best to back off rather than further irritate it.

Right. Don't corner venomous snakes.

Why do you want to corner and pepper spray a snake?
What kind of snake are you after?
Are you trying to catch it?