# Is SO a strong acid or not

The Equivalence point in an acid-base titration is the point at which a certain amount of acid has been neutralized with the corresponding amount of base. If acids and bases of the same strength are titrated with one another (pKS.(Acid) = pKB.(Base)), the equivalence point in aqueous solution is equal to the neutral point, (the pH value is 7). If, on the other hand, acids and bases of different strengths are titrated with one another, the resulting solution is not neutral at the equivalence point. For example, if a weak acid (e.g. acetic acid, CH3COOH) neutralized with the equivalent amount of a strong base, the pH is finally basic. This is because the acetate ions (CH3COO-), which is the corresponding base of the weak acid CH3Form COOH, now act as a base themselves and are therefore able to H+-Ions to capture, i.e. with H2O to CH3COOH and OH- to react. In the case of multi-protonic acids (e.g. H3PO4 or H2SO4) corresponds to the amount of substance to be added of the base, the amount of substance of the acid times the exponent of the acid-H ions, divided by the exponent of the hydroxide group of the base (formula see below) in order to achieve complete neutralization. The pH value here does not necessarily correspond to 7.

### Examples

More general

Let HxA is any acid, where x is the number of hydrogen ions (H.+) and A- denote the acid residue in the molecule. Let B (OH) y be any base, where y is the number of hydroxide ions (OH-) and B denotes the base residue in the molecule. Regardless of the respective pKS.- and pKB.Values ​​now apply to mutual neutralization in aqueous (!) Solution:

, n: amount of substance of acid, m: amount of substance of base

Thus, with a known acid and base and a known amount of substance of one of the two substances, the amount of substance required for neutralization of the other substance can easily be calculated.