At 2:00 PM -0700 3/29/07, Larry D. McLouth wrote: >What is your practice for storing nitric and hydrochloric acids? >Do you keep them separated to prevent mixing? > >I realize they are intentionally mixed to make aqua regia, (under >controlled conditions using a fume hood). But this evolves chlorine >and nitrosyl chloride gases...so there is a concern about storing >these two acids together. > >I plan to tell our users that it's okay to keep these two acids in >the same storage cabinet but that they should be kept on the same >shelf and in individual photo trays to prevent accidental mixing in >the event of a spill, leak etc. Hydrochloric and nitric acids are incompatible and should NOT be stored together. It says so on the MSDS for either. Just because "everyone does it" without major problems doesn't mean that the practice is recommended safe, and suggesting otherwise could set one up for some serious liability, no doubt. I actually see the gas phase reaction of the two being more likely than a double spill in the same cabinet. For example, many folks store their acids and "ammonium hydroxide" (concentrated aqueous ammonia) bottles in the same cabinet....and wonder why they are always coated with a white substance (ammonium hydroxide). Bases should always be stored away from acids, of course. From a practical sense, I know from my lab experience that many (most?) chemists store their hydrochloric and nitric acids in the same cabinet, if only because they can't dedicate a separate space. While trays are a good idea, a subdividing the cabinet so the two halves can't exchange air or liquid - or perhaps a sealed overcontainer within the cabinet, are probably better ideas. At the risk of self-promotion, Eagle Manufacturing and other companies make polyethylene acid storage cabinets that make the segregation of nitric and hydrochloric easier. Some of these have internal dividers/compartments. Alternatively, one can buy a small cabinet (4 gallon) for the nitric acid as hydrochloric and many other acids can be stored together. See here: http://www.safetyemporium.com/ILPI_Site/WebPagesUS/safety/cabinets.htm and click on any of the items for more detail and bigger pictures. Rob Toreki -- ===================================================== Safety Emporium - Lab & Safety Supplies featuring brand names you know and trust. Visit us at http://www.SafetyEmporium.com esales**At_Symbol_Here**safetyemporium.com or toll-free: (866) 326-5412 Fax: (859) 523-0606, 4905 Waynes Blvd, Lexington, KY 40513-1469
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