Which of the following is the correct set for $SiO_2$?

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:

Arrange the following in the decreasing order of their bond enthalpy: $H_2, O_2, N_2$.

During the formation of a chemical bond,

Which of the following statements is incorrect?
$(i)$ $NaCl$,being an ionic compound,is a good conductor of electricity in the solid state.
$(ii)$ In canonical structures,there is no difference in the arrangement of atoms.
$(iii)$ Hybrid orbitals form stronger bonds than pure orbitals.
$(iv)$ $VSEPR$ theory can explain the square planar geometry of $XeF_4$.

Which of the following contains both covalent and ionic bonds?