Concentrated sulfuric acid (about 98%, by weight) is about 36.8N. The Molarity is about 18.4 and the Normality is about 36.8. The 18N, then, is only about 49%, by weight.
In a feeble attempt to put this simply.
Mole (or, Mol), Molar, Molarity
If you get an atomic weight chart and look up the atomic weights of all the elements in a chemical's formula, and add them all together, you will have the weight, in grams, of one Mole of that chemical. In the case of sulfuric acid, H2SO4, there are 2 hydrogen atoms, 1 sulfur atom, and 4 oxygen atoms. The atomic weight of hydrogen is 1.008, sulfur is 32.06, and oxygen is 16. Therefore, the weight of 1 Mole of H2SO4 is:
(1.008 x 2) + (32.06 x 1) + (16 x 4) = 98.076 grams
The Molarity is the number of Moles in 1 liter of solution.
Therefore, a 1 Molar solution of H2SO4 would contain 98.076 grams of H2SO4 in 1 liter of solution.
Concentrated sulfuric is about 18.4 Molar. In other words, one liter of concentrated sulfuric contains about 18.4 x 98.076 = 1,805 grams of H2SO4
Normal, Normality
I won't go into the strict definition of Normality, except to say that, since H2SO4 contains 2 hydrogen atoms (H2), its Normality is twice its Molarity. Since nitric acid, HNO3, and hydrochloric acid, HCl, both only have 1 hydrogen atom, their Molarities are equal to their Normalities. Therefore, a 1 Normal solution of H2SO4 will only contain 1/2 Mole of H2SO4 (98.076/2 = 49.038 grams) per liter.
When you neutralize sodium hydroxide, NaOH, with an acid, the H from the acid combines with the OH of the sodium hydroxide, to form water, H2O. If you use, for example, HCl, it will take 1 Mole of HCl (36.461 grams) to neutralize 1 Mole of NaOH (40.00 grams). However, since H2SO4 has 2 hydrogens, 1 Mole of H2SO4 will neutralize 2 Moles of NaOH. All this has to do with what is called Normality.
Therefore, 1 liter of 98% concentrated 18.4 Molar H2SO4 will neutralize 18.4 x 2 Moles, or 36.8 Moles of NaOH = 36.8 x 40.00 = 1,472 grams
Confused? I surely could have done this better.
