JEE Main 2023 — Chemistry Inorganic Chemistry

${[\mathrm{Ni}(\mathrm{CN}{)}_{4}]}^{2-}:{\mathrm{Ni}}^{+2}=$[Ni(CN)4​]2−:Ni+2=

It is diamagnetic as $\mathrm{CN}-$CN− is a strong field ligand and forces electron pairing.

$[\mathrm{Ni}(\mathrm{CO}{)}_{4}]:\mathrm{Ni}=$[Ni(CO)4​]:Ni=

It is diamagnetic as carbonyl group is a strong field ligand and forces electron pairing.

${[{\mathrm{NiCl}}_{4}]}^{2-}:{\mathrm{Ni}}^{2+}=$[NiCl4​]2−:Ni2+=

It is paramagnetic as chloride group is a weak field ligand.

${[\mathrm{Fe}(\mathrm{CN}{)}_{6}]}^{4-}:{\mathrm{Fe}}^{2+}:$[Fe(CN)6​]4−:Fe2+:-

It is diamagnetic as $–\mathrm{CN}$–CN is a strong field ligand which causes pairing of electrons.

${[\mathrm{Cu}{({\mathrm{NH}}_{3})}_{4}]}^{+2}:{\mathrm{Cu}}^{+2}\Rightarrow$[Cu(NH3​)4​]+2:Cu+2⇒ Here Copper ion has one unpaired electron, thus it is paramagnetic as it is $3{d}^{9}$3d9 configuration.

${[\mathrm{Fe}(\mathrm{CN}{)}_{6}]}^{3-}:{\mathrm{Fe}}^{+3}:$[Fe(CN)6​]3−:Fe+3:

It is paramagnetic, here ${\mathrm{CN}}^{-}$CN− is a strong field ligand

${[\mathrm{Fe}{({H}_{2}O)}_{6}]}^{2+}:{\mathrm{Fe}}^{2+}:$[Fe(H2​O)6​]2+:Fe2+:

It is paramagnetic, here ${H}_{2}O$H2​O , here a weak field ligand