Question

Give reasons for the following :

$(C{H}_3{)}_3$ N is pyramidal but $(Si{H}_3{)}_3$ N is trigonal planar.

• A. In $(C{H}_3{)}_3$ $\stackrel{\bullet \bullet }{N}$, hybridisation is $s{p}^3$ and pyramidal shape
• B. but in $(Si{H}_3{)}_3\stackrel{\bullet \bullet }{N}$, due to the presence of vacant d-orbital in Si atom, lone pair of N is shifted in vacant orbital so its hybridisation is $s{p}^2$ with trigonal planar geometry
• C. $A$ and $B$
• D. None of these

Answer 1

Answer: (C)

$A$ and $B$

In $(C{H}_3{)}_3$ $\ddot{N}$, hybridisation is $s{p}^3$ and pyramidal shape but in $(Si{H}_3{)}_3$ $\ddot{N}$, due to present of vacant d-orbital in Si atom, lone pair of N is shifted in vacant orbital so its hybridisation is $s{p}^2$ with trigonal planar geometry.

Both the option A and B are facts and correct.