1 normal acid or base (1N)

Biologists are sometimes confused by the non-standard chemical unit of normality N. N refers in general to salts while it's most commonly used in the context of acid and bases. N can refere to either the cation or the anion in a hydrolysis. In the context of acid and bases it is generally assumed that N refers to the proton or the hydroxide ion.


 * 1 M (mol/l) = 1 N for an acid that releases 1 proton* when dissolved in water, e.g. HCL (*monoprotic)
 * 1 M (mol/l) = 2 N for an acid that releases 2 protons*, e.g. H2SO4 (*diprotic)

For example, some antigen retrieval methods use 2N hydrochloric acid to open up the tissue to allow antibody binding. This could be a nucleotide analogue, as BrdU or dUTP-TMR in cell proliferation of apoptosis assays.

1N, 2N HCl
1N HCl
 * 10 ml fuming HCl (37% v/v = 10N = 10M)
 * 90 ml H2O

2N HCl, see also
 * 20 ml fuming HCl (37% v/v = 10N = 10M)
 * 80 ml H2O

Molarity (M) also a non-standard unit
For the nitpickers, molarity M is also a non-standard unit. Expressing this explicitly as mol/L or mol/m3 is clearer to readers less versed in current biological customs.