$I)$ Bond order of $H _2^{-}=\frac{1}{2}[2-1]=0.5$

Bond order of $H _2^{+}=\frac{1}{2}[1-0]=0.5$

Bond order of $H _2=\frac{1}{2}[2-0]=1$

Bond order of $H _2$ is greater than $H _2^{-}$and $H _2^{+}$

$II)$ Bond order of $O _2^{+}=\frac{1}{2}[10-5]=2.5$

Bond order of $NO =\frac{1}{2}[10-5]=2.5$

Bond order of $N _2^{-}=\frac{1}{2}[10-5]=2.5$

$III)$ Bond order can have any value. And a bond order equal to zero implies

that there is no bond at all between the atoms.

$IV) \,NO _3^{-}$and $BO _3^{-}$ do not have same bond order.