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QAIPM-2002-Ph-2804: NEET 2002 Chemistry - Class 12 AIPM-2002-Ph-2804 Solution: Atomic number of Cr and Fe are respectively 24 and 26, which of …

Atomic number of Cr and Fe are respectively 24 and 26, which of the following is paramagnetic with the spin of electron?

Multiple Choice Options

  • A [Cr(CO)6][Cr(CO)_6]
  • B [Fe(CO)5][Fe(CO)_5]
  • C [Fe(CN)6]4−[Fe(CN)_6]^{4-}
  • D [Cr(NH3)6]3+[Cr(NH_3)_6]^{3+}

Step-by-Step Verified Solution

Atoms, ions or molecules containing unpaired electrons are paramagnetic. In [Cr(NH 3 ) 6 ] 3+ Cr +3 = [Ar]3d 3 4s 0 NH 3 is weak field ligand so pairing of d-electrons take place odes not happen. Here, Number of unpaired electrons = 3 So it is paramagnetic. In other cases pairing of d-electrons take place in presence of strong field ligands such as CO or CN � .

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