JEE Main · 2024 · 31 Jan 2024 · Shift 1 · Coordination Compounds

A. Crystal field theory (CFT) does not itself predict or explain why one anionic ligand is a stronger or weaker field ligand than another (that ordering is empirical, from the spectrochemical series) -- false as a claim about CFT's explanatory power.

B. Valence bond theory describes bonding and geometry but gives no quantitative treatment of the kinetic stability (lability/inertness) of coordination compounds -- true.

C. $[\mathrm{Ni}(\mathrm{CN}{)}_4{]}^{2-}$ is square planar with $ds{p}^2$ hybridisation (the strong-field $\mathrm{C}{\mathrm{N}}^{-}$ ligand pairs up the $d$-electrons of $\mathrm{N}{\mathrm{i}}^{2+}$) -- true.

D. The cis isomer of $[\mathrm{PtC}{\mathrm{l}}_2(\mathrm{en}{)}_2{]}^{2+}$ is chiral and exists as a pair of non-superimposable mirror images (optical isomers), so it has two possible isomers, not one -- false.

So the correct statements are B and C only.