Container of chlorine

Can be purchased from Ralph at Mick and Ralph's in Freeside. Can also be found in a storage room of the Ultra-Luxe. During the quest How Little We Know if you side with Nero and Big Sal by turning Cachino in, Big Sal has you talking to Clanden whom gives you specifc instructions on where the find the container of chlorine if player passes [science] check. So, the container of chlorine is used to make a chlorine bomb which is evidently used during the fight for Hoover Dam.