Chemistry - CHEMICAL BONDING Question with Solution | TestHub

(A) Mn⁺=3d⁵4s¹;in presence of CO, effective configuration=3d⁶4s⁰.
Three lone pair for back bonding with vacant orbital of C in CO.
(B)$\mathrm{F}{\mathrm{e}}^0=3{\mathrm{d}}^{6}4{\mathrm{s}}^2$;in presence of CO, effective configuration$=3{\mathrm{d}}^8$.
Four lone pair for back bonding with CO.
(C)$\mathrm{C}{\mathrm{r}}^0=3{\mathrm{d}}^{5}4{\mathrm{s}}^1$;effective configuration$=3{\mathrm{d}}^6$.
Three lone pair for back bonding with CO.
(D)${\mathrm{V}}^{-}=3{\mathrm{d}}^{4}4{\mathrm{s}}^2$;effective configuration$=3{\mathrm{d}}^6$.
Three lone pair for back bonding with CO.
Maximum back bonding is present in$\mathrm{F}\mathrm{e}(\mathrm{C}\mathrm{O}{)}_5$​therefore, CO bond order is lowest here.