Among the trihalides of nitrogen which one is most basic
Answers
Explanation:
thought that the order should be NF3 > NI3 > NBr3 > NCl3 because:
all the halides except fluorine have vacant d-orbitals. So, back-bonding should reduce the basicity of all but NF3.
NCl3 shows more effective back-bonding as compared to NBr3 which shows more effective back-bonding than NI3. Better the back-bonding, lesser is the availability of the lone pair on the nitrogen atom.
It seems to imply that electronegativity is a more dominant factor as compared to back-bonding. But when we compare the acidity of boron tri-halides, we consider back-bonding to be the dominant factor. Same goes for Ipso effect.
PSS: I often come across questions of this sort which ask me to compare acidity & basicity of two or more compounds(both organic & inorganic). I think of looking at the pKb/pKa values of the chemicals can help me to reliably get the order in some cases. But I couldn't find any source/compilation of those values. Do you know any source which lists the pKb/pKa values of chemicals? If so, please add it to your answer. It may prove to be really useful for me & other people