For a reaction scheme $$A\buildrel {{k_1}} \over \longrightarrow B\buildrel {{k_2}} \over \longrightarrow C$$,

if the rate of formation of B is set to be zero then the concentration of B is given by :

The major product of the following reaction is:

Among the following molecules / ions, $$C_2^{2 - },N_2^{2 - },O_2^{2 - },{O_2}$$ which one is diamagnetic and has the shortest bond length?

The calculated spin-only magnetic moments (BM) of the anionic and cationic species of [Fe(H₂O)₆]₂ and [Fe(CN)₆], respectively, are :