I looked, also, and didn't find an answer in print that answers the question in so many words ut I think you're right and for this reason.
If we look at the hydrolysis of each we have
CN^- + HOH ==> HCN + OH^-
Kb for CN^- = Kw/Ka for HCN. Ka for HCN is approx 10^-10 so Kb for CN is approx 1E-14/1E-10 = 1E-4.
For C2^2- + 2HOH ==> C2H2 + 2OH^-
Kb for (C2)^2 = Kw/Ka for HCCH. If you google acetylene you will find pKa of 25 for those H atoms so
Kb = 1E-14/1E-25 = 1E11 which makes Kb for (C2)2- much stronger than that for CN^-
Hope this helps.
Which of the following is a stronger lewis base: cyanide ion or dicarbide ion?
I'm assuming it is the dicarbide ion as it is more negatively charged and a compound consisting of 2 carbons is larger and therefore more likely to lose electrons than something consisting of carbon and nitrogen. I've extensively searched the internet looking for an answer and have yet to come across a definitive solution.
1 answer