Among the following species, the diamagnetic molecule is

The correct statements among I to III are :
(I) Valence bond theory cannot explain the color exhibited by transition metal complexes.
(II) Valence bond theory can predict quantitatively the magnetic properties of transtition metal complexes.
(III) Valence bond theory cannot distinguish ligands as weak and strong field ones.

HF has highest boiling point among hydrogen halides, because it has :

Among the following, the molecule expected to be stabilized by anion formation is :
C₂, O₂, NO, F₂