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

Observe the following sets:

Label	Order	Property
$i.$	$NH_3 > H_2O > SO_2$	Bond angle
$ii.$	$H_2O > NH_3 > H_2S$	Dipole moment
$iii.$	$N_2 > O_2 > H_2$	Bond enthalpy
$iv.$	$NO^{+} > O_2 > O_2^{2-}$	Bond order

Which of the above sets are correctly matched?

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 $CuCl$.

Match the following columns:

Column-$I$	Column-$II$
$(P)$ $\underline PCl_5 \to PCl_3 + Cl_2$	$(i)$ Change in hybridisation
$(Q)$ $\underline SO_3 \to \underline SO_2 + \frac{1}{2}O_2$	$(ii)$ Change in bond angle
$(R)$ $\underline NH_3 + H^{+} \to \underline NH_4^+$	$(iii)$ Change in shape
$(S)$ $H_2\underline O + H^{+} \to H_3\underline O^{+}$	$(iv)$ Change in oxidation state

Which of the following is an incorrect statement?

The $P-P-P$ bond angle in $P_4$ and $S-S-S$ bond angle in cyclo $S_8$ molecule are respectively