In the $OF_2$ molecule,the number of bonding and lone pairs of electrons are,respectively,........

What is chemical bonding? How is it formed,and what are its types?

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:

Consider the following species and select the incorrect statement $:-$ $NH_3, PCl_4^{\oplus}, NH_2^{-}, SO_2, SO_3, BF_3, PCl_3, IF_7$

$CO$ has the same number of electrons as which of the following ions? Or,which ion is isoelectronic with $CO$?

Which of the following compounds can exist?