How nitric acid overcame its fear of water with a little help from its friends

Whether it is a pond or raindrop, when a common nitrogen-containing acid encounters water's surface, it typically falls apart, dissociating into two charged particles. Except, sometimes it is able to hold it together, not entirely but noticeably. Researchers discovered that nitric acid, or HNO3, dissociates less because it gains structure by building more connections at higher concentrations. When enough acid is present, the molecules build hydrogen bonds that reduce dissociation. At lower concentrations, these bonds don't form.  More...

http://www.physorg.com/news/2012-03-nitric-acid-overcame-friends.html