Identify the pair that is not isostructural.

What is an ionic bond? With two suitable examples,explain the difference between an ionic and a covalent bond.

The $B-F$ bond dissociation energy in $BF_3$ is $646 \, kJ \, mol^{-1}$,whereas the $C-F$ bond dissociation energy in $CF_4$ is $515 \, kJ \, mol^{-1}$. Which of the following is the correct reason for the $B-F$ bond dissociation energy being higher than the $C-F$ bond dissociation energy?

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

Observe the following statements:
$i$. The dipole moment of $NH_3$ is higher than the dipole moment of $NF_3$.
$ii$. The dipole moment of chloroform $(CHCl_3)$ is zero.
$iii$. Covalent bond character in $NaCl$ is more compared to $CuCl$.

The correct statement among the following is: