pKa is a value which is related to the acid dissociation constant Ka
pKa = -log Ka
i.e. Ka = 10^-pKa
The deprotonation reaction of acetylene is:
HC≡CH ↔ HC≡C⁻ + H⁺
pKa (HC≡CH) = 25
Solvents with pKa greater than 25 will deprotonate acetylene.
Ans: CH2=CH⁻ pka = 44 and CH3NH⁻ pka = 40