which is stronger base?NF3 or NCl3??i thought NF3 is better...i know fluorine is more electronegative than nitrogen so will pull the lone pair of nitrogen towards itself and reduce the tendancy to donate electron pair..but on the other hand,there is back bonding between electron pair of N and vaccant d orbital of Cl..so electron pair is not available for donating...so what should be the answer now???

will pull the lone pair of nitrogen towards itself and reduce the tendancy to donate electron pair.but it is not possible.pulling of electron is possible only when one of the bonded atom has large size and the other has very small size with respect to other bonded atom.for example:hcl.in hcl,cl tries to pull the bonded pair of electron towards it.

                                                     when coming to ncl₃,cl does not have d-orbital electron.because electronic configuration of cl is 1s²2s²2p⁶3s²3p^5.