For hydrazoic acid, which of the following resonating structure will be least stable?

$\underset{\left(\mathrm{I}\right)}{\mathrm{H}-\mathrm{N}={\mathrm{N}}^{+}={\mathrm{N}}^{-}}\leftrightarrow \underset{\left(\mathrm{II}\right)}{\mathrm{H}-{\mathrm{N}}^{+}-{\mathrm{N}}^{+}={\mathrm{N}}^{2-}}\leftrightarrow \underset{\left(\mathrm{III}\right)}{\mathrm{H}-{\mathrm{N}}^{-}-{\mathrm{N}}^{+}\equiv \mathrm{N}}$

Which of the following overlaps is incorrect [assuming $\mathrm{z}-$axis to be the internuclear axis]?

(a) $2{\mathrm{p}}_{\mathrm{y}}+2{\mathrm{p}}_{\mathrm{y}}\to \mathrm{\pi }2{\mathrm{p}}_{\mathrm{y}}$

(b) $2{\mathrm{p}}_{\mathrm{z}}+2{\mathrm{p}}_{\mathrm{z}}\to \mathrm{\sigma }2{\mathrm{p}}_{\mathrm{z}}$

(c) $2{\mathrm{p}}_{\mathrm{x}}+2{\mathrm{p}}_{\mathrm{x}}\to \mathrm{\pi }2{\mathrm{p}}_{\mathrm{x}}$

(d) $1\mathrm{s}+2{\mathrm{p}}_{\mathrm{y}}\to \mathrm{\pi }(1\mathrm{s}-2{\mathrm{p}}_{\mathrm{y}})$

Identify the correct match.

In which of the following molecules/species are all following characteristics are found:

(a) Tetrahedral hybridisation

(b) Hybridisation can be considered to have taken place with the help of empty orbital(s).

(c) All bond lengths are identical, i.e., all $\mathrm{A}-\mathrm{B}$ bond lengths are identical.

Correct statement regarding this reaction:

${\mathrm{BF}}_3+{\mathrm{NH}}_3⟶\left[{\mathrm{F}}_3\mathrm{B}\leftarrow {\mathrm{NH}}_3\right]$