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

The ratio of $\sigma$-bond and $\pi$-bond in tetracyanoethylene is

The pairs among $A = [SO_3^{2-}, CO_3^{2-}]$, $B = [O_2^{2-}, F_2]$, $C = [CN^-, CO]$, $D = [NH_3, H_3O^+]$ and $E = [MnO_4^{2-}, CrO_4^{2-}]$ that do not have similar Lewis dot structures are:

What do you mean by strength and reactivity of a bond?

The number of bonds between sulphur and oxygen atoms in $S_{2}O_{8}^{2-}$ and the number of bonds between sulphur and sulphur atoms in rhombic sulphur,respectively,are

Amongst the following,the number of oxide$(s)$ which are paramagnetic in nature is $Na_2O$,$KO_2$,$NO_2$,$N_2O$,$ClO_2$,$NO$,$SO_2$,$Cl_2O$.