What is the pKa of an amide?
Amide. pKa = -0.4. A protonated amide possesses the least acidic group of them all (CONH+), proof that the blinking resonance form has in this case an overwhelming contribution.
What is the pKa of methanol?
15.5
One could not use the reported pKa values of methanol (pKa = 15.5) based on approximate activities and water (pKa = 15.7) based on concentrations in aqueous solution as evidence to indicate that methanol is slightly more acidic than water in aqueous solution because the pKa value (15.7) for water is not …
What is pKa of pure water?
15.7
Since [H2O] in pure water is 55.5 M, Ka = 1.8 x 10E-16, or pKa = 15.7 .
What does the pKa table tell you about thiol?
Both are incorrect. The reaction that happens is the simplest one – deprotonation of SH, to provide water and the deprotonated thiol. Also, the pKa table tells you about leaving group ability. Good leaving groups are weak bases!
How is the strength of an organic acid related to PKA?
approx. 60 For strengths of organic acids see E. P. Serjeant and B. Dempsey (eds.), Ionization Constants of Organic Acids in Solution, IUPAC Chemical Data Series No. 23, Pergamon Press, Oxford, UK, 1979. The strength of a base is related to the pKaof its conjugate acid as pKb= 14 – pKa.
Which is the best base for PKA vaules?
Name Acid / Conjugate base pKa Sulfuric acid -10 Hydrogen iodide -10 Hydrogen bromide -9 Hydrogen chloride -7 Acetone conjugate acid -7 Benzenesulfonic acid -6.5 Acetic acid conjugate acid -6 Diethyl ether conjugate acid -3.5 Ethanol conjugate acid -2 Methanesulfonic acid -2 Hydronium ion -1.74 Nitric acid -1.5 Trifluoroacetic acid 0.5
Which is more acidic alcohol or thiolate anion?
Sulphur atoms of thiols are more nucleophilic than that of oxygen atoms in alcohol. These thiol groups are fairly acidic with a pKa of around 10 to 11. Moreover, in the existence of a foundation, a thiolate anion is created that is a fairly powerful nucleophile. Additionally, this group and its associated anions are readily oxidised.