The pair having the same magnetic moment is

The pair having the same magnetic moment is:

[At. No.: Cr = 24, Mn = 25, Fe = 26, Co = 27]

  1. [Cr(H2O)6]2+ and [Fe(H2O)6]2+
  2. [Mn(H2O)6]2+ and [Cr(H2O)6]2+
  3. [CoCl4]2– and [Fe(H2O)6]2+
  4. [Cr(H2O)6]2+ and [CoCl4]2–

Solution

Cr2+ is in d4, so number of unpaired electron = 4

Fe2+ is in d6, so number of unpaired electrons = 4

Both configurations have 4 unpaired electrons due to weak field ligands.

The correct option is A.