Arrange the following molecules according to the decreasing order of their $O-O$ bond lengths.

Select the incorrect statement about $N_2F_4$ and $N_2H_4$ :
$(I)$ In $N_2F_4$,$d$-orbitals are contracted by electronegative fluorine atoms,but $d$-orbital contraction is not possible by $H$ atoms in $N_2H_4$.
$(II)$ The $N-N$ bond energy in $N_2F_4$ is more than the $N-N$ bond energy in $N_2H_4$.
$(III)$ The $N-N$ bond length in $N_2F_4$ is more than that in $N_2H_4$.
$(IV)$ The $N-N$ bond length in $N_2F_4$ is less than that in $N_2H_4$.
Choose the correct code:

What is the decreasing order of $C - C$ bond length in the following compounds?
$[I]$ $C_2H_4$
$[II]$ $C_2H_2$
$[III]$ $C_6H_6$
$[IV]$ $C_2H_6$

In the electronic structure of acetic acid $(CH_3COOH)$,there are:

The pair of molecules/ions with the same geometry but central atoms in different states of hybridization is:

In the following electron-dot structure, calculate the formal charge from left to right for the nitrogen atoms: $: \ddot{N} = N = \ddot{N} :$