Question

Sol. (A) PBr₅(s) → PBr₄⁺ + Br^Θ

PBr₄^⊕ ⇒ geometry: - tetrahedral

Hybridization: - sp³

(B) $\underset{EAN = 37}{\lbrack Co(NH_{3})_{6}\rbrack^{+ 2}}\overset{\quad - e^{\Theta}\quad}{\rightarrow}\underset{EAN = 36}{\lbrack Co(NH_{3})_{6}\rbrack^{+ 3}}$

$\underset{EAN = 37}{\lbrack Co(NO_{2})_{6}\rbrack^{- 4}}\overset{\quad - e^{\Theta}\quad}{\rightarrow}\underset{EAN = 36}{\lbrack Co(NO_{2})_{6}\rbrack^{- 3}}$

Both are oxidisable

(D) $d_{z^{2}}$ orbital never used in dsp²- hybridization.