What is the definition of acid dissociation constant i.e, Pl. state the difference between pka and ka value & Why is ka2 of sulphuric acid less than ka1?
An acid dissociation constant, Ka, (also known as acidity constant, or acid-ionization constant) is a quantitative measure of the strength of an acid in solution. It is the equilibrium constant for a chemical reaction known as dissociation in the context of acid-base reactions. The equilibrium can be written symbolically as:
- HA A? + H+,
- The logarithmic constant, pKa, which is equal to ?log10 Ka, is sometimes also (but incorrectly) referred to as an acid dissociation constant:
- sulphuric acid is a diacid.Ka1 is the dissociation constant when it dissociates and one proton is released.HSO4- is formed which again dissociates but because of one negative charge now present on the molecule removal of proton is a bit difficult hence the dissociation constant for the abstraction of second proton from sulphuric acid is less .