According to $MO$ theory,the molecule which contains only $\pi$-bonds between the atoms is

In which of the following processes,the bond order increases and paramagnetic character changes to diamagnetic one?

Using $MOT$,compare $O_{2}^{+}$ and $O_{2}^{-}$ species and choose the incorrect option.

Given below are two statements:
Statement $I$: $A$ $\pi$ bonding $MO$ has lower electron density above and below the inter-nuclear axis.
Statement $II$: The $\pi^*$ antibonding $MO$ has a node between the nuclei.
In the light of the above statements,choose the most appropriate answer from the options given below:

In $O_2^-$,$O_2$,and $O_2^{2-}$ molecular species,the total number of antibonding electrons respectively are

Arrange the molecules $B_2, He_2, N_2$ and $C_2$ in the increasing order of their bond order values.