Question

The compound that is not a Lewis acid is :

• A. $B{F}_3$
• B. $AlC{l}_3$
• C. $BeC{l}_2$
• D. $SnC{l}_4$

Answer 1

The correct option is D $SnC{l}_4$

Electron acceptors that have either incomplete octet or empty orbitals are Lewis acids.
In, $B{F}_3$, Boron has only $6e^{-}$ in its valance shell even after bonding with 3 fluorine atoms and hence can accept 2 more electrons to complete its octet.
In, $AlC{l}_3$ also Al has 6 electrons in valance shell and can accept 2 more electrons.
In, $BeC{l}_2$, Be has only $4e^{-}$ in valance shell and can accept 4 more electrons. Hence $B{F}_3$, $AlC{l}_3$, $BeC{l}_2$ are Lewis acids.
In $N{H}_3$, the octet of N is complete with 8 electrons. So, $N{H}_3$ is not an Lewis acid.