ohitmustbe - 5-10-2006 at 00:08
In chemistry what does N stand for (not in a nitrogen context, but rather in a concentration context) Surely it isn't interchangable with M correct.
Can you please help me?
woelen - 5-10-2006 at 03:09
N stands for "normality". It specifies the active equivalent.
For acids it stands for active equivalent concentration of H(+).
For acids like HCl, HBr, HClO4, and all other single-proton acids, a concentration M is equivalent to an active equivalent concentration N. But for
H2SO4, N is two times M. A 1 M concentration has 2 mol/l of equivalent H(+), so a 1 M concentration of H2SO4 is a 2 N solution of H2SO4.
For oxidizers, a similar concept is used, but now the number of electrons, which can be transferred per mol of species is used as the active
equivalent.
E.g. Br2 + 2e --> 2Br(-)
For this, a 1 M solution is a 2 N solution
For acidified permanganate: MnO4(-) + 5e + 8H(+) ---> Mn(2+) + 4H2O
For this, a 1 M (in permanganate) solution is a 5 N solution, and a 0.01 M solution is a 0.05 N solution.
For bases, the number of available OH(-) is used as active equivalent.
For reductors, the number of electrons, used up by 1 mol of reductor is used as active equivalent, e.g. for sulfite, 1 M is 2 N (two electrons per
sulfite ion, which is transformed to sulfate).