Identify (A) in the following reaction sequence :

If enthalpy of atomisation for Br₂₍₁₎ is x kJ/mol and bond enthalpy for Br₂ is y kJ/mol, the relation between them :

[Pd(F)(Cl)(Br)(I)]^2– has n number of geometrical isomers. Then, the spin-only magnetic moment and crystal field stabilisation energy [CFSE] of [Fe(CN)₆]^n–6, respectively, are:
[Note : Ignore the pairing energy]

If the magnetic moment of a dioxygen species is 1.73 B.M, it may be :