See image — AITS & Test Series Chemistry Question

💡 Solution & Explanation

The electronic configurations of Ni, Fe, CO and Cr in the given complexes are   8 3d ,    6 6 3 , 3 d d and   4 3d , respectively. These involves dsp², d²sp³, d²sp³ and sp³ d²-hybridizatin respectively. The complex   2 4 6 Cr H O SO     will be paramagnetic as Cr contains four unpaired electrons.