Are disposable latex gloves safe to use with ferric chloride etchant?

no problem,,,,,,that ferric chloride solution is water or aqueous based.   water doesn;t dissolve rubber (latex) so you'll be fine.   careful about where you spill or splash that stuff....it'll eat tiny holes (after enough wash cycles, taht is..._) thorugh your clothes.

if you have extra gloves, try spraying a little wd40 or other oil based liquid onto one.    that will destroy the latex....it may take a few minutes but it'll show you the difference.   wd40 is PETROLEUM based which is essentially an oil.....loves to eat latex.