Co-ordination Compounds MCQs for NEET — Chemistry Questions with Answers

Among the given options, $[Fe(H_2O)_6]^{+2}$ has the highest paramagnetism. This is because it has the maximum number of unpaired electrons compared to the other ions listed. Iron(II) in $[Fe(H_2O)_6]^{+2}$ has 4 unpaired electrons (d^6 configuration), making it the most paramagnetic.

The compound nitro pentamine chromium (III) chloride exhibits linkage isomerism. This is because the nitro group (NO2) can bind to the metal center either through the nitrogen atom (nitro) or through the oxygen atom (nitrito), leading to two different isomers.

The complex compound $[Co(NH_3)_3 (NO_2)_3]$ is a poor electrolytic conductor in solution because it does not dissociate into ions easily. Unlike ionic compounds, which dissociate to give ions that conduct electricity, this complex remains largely intact in solution, thereby conducting electricity poorly.

Paramagnetism is due to the presence of unpaired electrons. In $[NiCl_4]^{2–}$, nickel is in the +2 oxidation state and has the electronic configuration 3d^8. Chloride ions are weak field ligands and do not cause pairing of electrons. Therefore, $[NiCl_4]^{2–}$ has two unpaired electrons, making it paramagnetic.

In $Ni(CO)_4$, nickel is in the zero oxidation state and has the electronic configuration 3d^8 4s^2. Carbon monoxide (CO) is a strong field ligand and causes pairing of electrons. Thus, $Ni(CO)_4$ has no unpaired electrons and is diamagnetic.

$[Co(NH_3)_3Cl_3]$ does not show optical isomerism because it is a symmetrical molecule and lacks chirality. The other complexes listed can form non-superimposable mirror images, hence they can have optical isomers.

The tetrammine copper (II) sulphate complex, [Cu(NH3)4]SO4, typically exhibits a blue color. This is due to the d-d electronic transitions that occur in the copper ion when it is complexed with ammonia ligands.

The cuprammonium ion, [Cu(NH3)4]^{2+}, adopts a square planar geometry. This is because copper (II) has a d^9 electronic configuration which leads to a preference for a square planar coordination to minimize repulsions and stabilize the complex.

In the complex [Ni(H2O)6]^{2+}, the nickel ion is in an octahedral environment formed by six water molecules. The hybridization involved in this geometry is sp^3d^2, which allows the formation of six equivalent bonds oriented at 90 degrees to each other.