Which one of the following molecules contains both ionic and covalent bonds?

Select the correct order:
$(a)$ $CO < CO_2 < CO_3^{2-}$ $\Rightarrow$ Bond length
$(b)$ $O_2 < O_3 < O_2^{2-}$ $\Rightarrow$ Bond length
$(c)$ $N_2 < N_2^+$ $\Rightarrow$ Bond energy

Assertion : Bond angle of $H_2S$ is smaller than $H_2O$.
Reason : Electronegativity of the central atom increases,bond angle decreases.

Which of the following pairs of molecules contains an odd-electron molecule and an expanded octet molecule?

If in $NH_3$ formation $N$ uses its pure atomic orbitals,then the wrong statement is:

In which of the following compounds is the octet complete $(C)$ or incomplete $(IC)$ for all atoms?
$Al_2Cl_6$ $-$ $Al_2(CH_3)_6$ $-$ $AlF_3$ $-$ Dimer of $BeCl_2$ $-$ Dimer of $BeH_2$
(Note: $C$ for complete octet and $IC$ for incomplete octet.)