Bond order normally gives idea of stability of a molecular species. All the molecules viz. H ₂, Li ₂ and B ₂ have the same bond order yet they are not equally stable. Their stability order is :

Step-by-step solution

The molecular orbital configuration of the given molecules is H ₂= 1 s^2 (no electron anti-bonding) Li ₂= 1 s^2 ^* 1 s^2 2 s^2 (two anti-bonding electrons) B ₂= 1 s^2 ^* 1 s^2 2 s^2 ^* 2 s^2 2 p_y^1= 2 p_z^1 (4 anti-bonding electrons) Though the bond order of all the species are same ( B . O =1) but stability is different. This is due to difference in the presence of no. of anti-bonding electron. Higher the no. of anti-bonding electron lower is the stability hence the correct order is H ₂> Li ₂> B ₂