You might also try a can of old fashioned oven cleaner with lye. Will eat right through clothing and cuse significant burns. Will also cause permanent blindness so don’t use unless you mean it
In many states, throwing an alkaline substance, or a lot of other things, in someone’s eyes is a serious crime.
Now, if you are in fear for your life, and it is truly all you have available...
But if you are in fear for your life, why not use the firearm?