It refers to the acidity of the fatty acid (which make up the oils). Every fatty acid is composed of a non-polar long chain of hydrocarbons (carbon and hydrogen) and a polar head made up of Carboxylic ACID. Every acid has something called pKa which determines the acidity of that acid.
The bigger the pKa (e.g. 25), the weaker the acid.
The smaller ther pKa (e.g. 2), the stronger the acid.
pKa = - log Ka so pKa - log Ka = 2 pKa or 2(-log Ka)
pKa is the acid dissociation constant for any acid. It is a measure of strength of the acid.
Ka is the equilibrium constant for an acid reaction. pKa is the -log of Ka
Just like you take -log of concentration of H to get pH, you take -log of Ka to get pKa
~26
pKa (dissociation constant) is variable with temperature.
pKa = -log KapKa = -log 5.4x10^-10pKa = 9.27
All you need to do to get Ka is to take the antilog of the pKa.
How can you calculate pka valve if ph is given?
By following + or - 2 pH to the pKa value
pKa of methanol is 15.5 see this pdf for more information about pka-values: http://chemweb.unp.ac.za/chemistry/Physical_Data/pKa_compilation.pdf
pKa=40
how do you calculate pKa
pKa=2.86
pKa = 15
It is around pKa=13
Doxofylline Pka value is about 9.8.
pKa (dissociation constant) is variable with temperature.
The pka of a protonated ether (the conjugate acid) is about -3.5
The pKa of sulfonic acid is < 0
pKa of drug can be determined from Handerson Hasselbatch equation., when conc. of salt become equal to acid i.e. at equivalence point when pH=pka then in H-H equn, pH=pka
pKa = -log KapKa = -log 5.4x10^-10pKa = 9.27