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Grade upto college level Physical Chemistry

(SiH3)3 N is a weaker base than (CH3)3 N. Give reason.

Profile image of aditya kashyap
12 Years agoGrade upto college level
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2 Answers

Profile image of Gaurav
11 Years ago
N atom in (SiH3)3 N is sp2 hybridized with a lone pair of electrons in 2p orbitals which can be transferred to the empty d orbital of Si atom. This reduced the electron density over N atoms and thus reduced its basic strength255-540_Untitled.png
In case of (CH3)3 N, there is no sucj transfer of electrons from N to the C atoms.
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Profile image of priya
9 Years ago
the geometry around trimethyl around N atom in (ch3)3N is pyramidal due to sp3 hybridisation and due to lone pair – bond pair repulsion.
In case of (Sih3)3 N, the atom is sp2 hybridised and the lone pair is present in the 2p orbitaland it is transferred to empty d orbital of Si atomforming dpi – p pi bond. Thus the involvement of lone pair in d pi – p pi bond makes (Sih3)3N a weaker base than (ch3)3 N.