Question

In which of the following, all the bond lengths are not the same?
I) $I{F}_4^{+}$
II) $B{F}_4^{-}$
III)$S{F}_4$
IV) $TeC{l}_4$

• A. $I,II,IV$
• B. $II,III,IV$
• C. $I,III,IV$
• D. $I,II,III$

Answer 1

Answer: (C)

$I,III,IV$

• $I{F}_4^{+}$ has $s{p}^{3}d$ hybridisation, two $F$atoms occupy equatorial position having same bond length and two $F$atoms occupy axial position having same bond length and the molecule acquires see-saw shape. Thus, all the bond lengths are not the same.
• $B{F}_4^{-}$ is $s{p}^3$ hybridised and has tetrahedral shape with equal bond lengths of all the four bonds.
• $S{F}_4$ and $TeC{l}_4$ both have $s{p}^{3}d$ hybridisation and one equatorial position is occupied by a lone pair in both. Therefore, both acquire see-saw shape with two equal axial bonds and two equal equatorial bonds. Thus, have bonds different bond lengths.