http://www.furrowpump.com/Applications/JarTesting/Explanationph.htmGenereal idea for using normality is to simplify stoichiometry of reaction to 1:1 ratio of reagents.
Hence normality may depends on reaction used. But if not stated, for which reaction the reagent should is involved, some general rules are used.
Denominator (n) in formula MM/n for calculation of equivalents is
For acids - number of exchangeable protons
for bases - number of exchaneeable hydroxyl groups
For salts - number of total charges of cations or anions
For an example of the specific reaction (stated by Borek)
Ba(2+) + SO4(2-) =BaSO4(s)
we can use general rules or its extension, just for this reaction (n=1 for both reagents), and still stoichiometry will be 1:1.
For the reaction, eg
NaCl + H2SO4 = NaHSO4 + HCl (this is stoichiometry for RT) we should use n=1 for H2SO4