I once asked the guy sitting next to me if he had any Sodium Hypobromite... He said, "NaBrO."
Sodium Hypobromite
Explanation
Explain Bear
Alright listen up, smarty pants! This joke is funny because "NaBrO" sounds like "Nah Bro," which is like saying "no" in a cool way. The dude is playing with chemistry terms to make a joke, but you probably already knew that, huh?