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=40
how do you calculate pKa
pKa=2.86
Generally speaking, the pH scale is good at relaying the concentration of the hydronium ion in an aqueous solution. I can tell you that a STRONGLY ACIDIC solution would give you a pH of roughly 0 or maybe even as far as just under -1. The pH of concentrated sulfuric acid (18M) is about -1.2. Still although a pH of less than 0 is certainly strongly acidic, I wouldn't necessarily call it a strong acid. I can tell you that hydrofluoric acid (HF) is a weak acid while hydrobromic acid (HBr) is strong but if I add a drop of HBr to a barrel of water and add a two cups of HF to a gallon of water, the HF solution will have a lower pH than the HBr solution and would be more strongly acidic (even though HF is a weaker acid). Instead of using pH to characterize acid strength, I'd probably look at pKa. pKa is a measure of a molecules intrinsic ability to give up a proton...the lower the pKa, the more strongly acidic a molecule is. Because we're so water based in our thinking, we usually say any thing that is a stronger acid than the hydronium ion (H3O+) is a strong acid. The hydronium ion is the strongest acid that can exist in water and has a pKa of roughly -1.7 so anything that has a pKa of less than -1.7 would be considered a strong acid and better at protonating a base than the hydronium ion. HSbF6, fluoroantimonic acid, is THE strongest acid with a pKa of roughly -25. That makes it about 100,000,000,000,000,000,000,000 more acidic than the hydronium ion and a superacid. Let me know if you want to know what pKa quantitatively means.
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 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 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