N, or normality, is a measure of the acid concentration of the solution.
Concentrated hydrochloric acid is 37% hydrogen chloride (37 grams of HCl per
100 ml of concentrated hydrochloric acid).  This is roughly 12 N.  2 N
hydrochloric acid would be roughly 6% HCl, and 0.5 N would be about 1.5%
HCl.  Since HCl is a gas, we have use it in solution.
Concentrated sulfuric acid is a pure liquid; it is about 18 N in acid
concentration.

Allen A. Smith, Ph.D.
Barry University
School of Graduate Medical Sciences
    Podiatric Medicine and Surgery
Miami Shores, Florida  33161-6695 

-----Original Message-----
From: Charles Read [mailto:csu15397@mail.claytonstate.net]
Sent: Monday, January 20, 2003 3:36 PM
To: histonet@pathology.swmed.edu
Subject: HCl Question....


Hello!  While reading through the  Fisher Sci. chemical catalog I noticed
that in the Hydrochloric Acid section there were many types of HCl, but the
only difference was one was labeled 0.5N, another labeled 1N and some were
labeled 2N, what does this refer to?  How does it change it's use?  Thanks
guys!