Among the following species, identify the isostuctural pairs
`NF_(3). NO_(3)^(-), BF_(3), H_(3)O, HN_(3)`

Options

A. `[NF_(3), NO_(3)^(-)] and [BF_(3), H_(3)^(+)O]`
B. `[NF_(3), NH_(3)], [NO_(3)^(-), BF_(3)]`
C. `[NF_(3), H_(3)^(+)O] and [NO_(3)^(-), BF_(3)]`
D. `[NF_(3), H_(3)^(+)O] and [HN_(3), BF_(3)]`

Answer

c

Explanation

For species to be isosturtu8ral they should have same hybridized state same number of `b.p.` and `l.p.`

Hybridized statye
`NF_(3) H = (1)/(2) (5+3) = 4 implies N is sp^(3)`hybridized `1`
`NO_(3)^(-) H = (1)/(2) (5+1) = 3 implies N is sp^(3)`hybridized `0`
`BF_(3) H = (1)/(2) (3+3) = 3 implies N is sp^(3)`hybridized `0`
`B_(3)O^(+) H = (1)/(2) (6+3-1) = 4 implies O is sp^(3)`hybridized `1`
These three `sp^(2)`- hydrid orbitals are attached to each other trigonally with an angle `120^(@)` and they are overlap with three p-orbitals of three F-atom on their exes. Hence the geometry of `BF_(3)` molecule is trigonal planer

Thus isostructure pairs are `[NF_(3), H_(3)O^(+)]` and `[NO_(3)^(-), BF_(3)]`