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The pair having the same magnetic moment is : [At. No. : Cr = 24, Mn = 25, Fe = 26, Co = 27] (1) [Cr(H2O)6]2+ and [CoCl4]2− (2) [Cr(H2O)6]2+ and [Fe(H2O)6]2+ (3) [Mn(H2O)6]2+ and [Cr(H2O)6]2+ (4) [CoCl4]2− and [Fe(H2O)6]2+

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

Correct answer: [Cr(H2O)6]2+ and [Fe(H2O)6]2+

Solution

Both [Cr(H2O)6]2+ and [Fe(H2O)6]2+ have the same number of unpaired electrons, resulting in identical magnetic moments despite their different atomic numbers. This similarity in unpaired electrons leads to comparable magnetic properties.

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