Two complexes Cr H 2 O 6   Cl 3   A and Cr NH 3 6 Cl 3 B are violet and yellow coloured,…

Two complexes CrH2O6 Cl3 A and CrNH36Cl3B  are violet and yellow coloured, respectively, The incorrect statement regarding them is:
  1. Both are paramagnetic with three unpaired electrons
  2. Δ0 value of A is less than that of B
  3. Δ0 values of A and B are calculated from the energies violet and yellow light, respectively.
  4. Both absorb energies corresponding to their complementary colors.

Solution

∆0A<∆0B , both complex have CN=6, B has strong field ligand and A has weak field ligand

so ∆0A< ∆0B

In both complexes, Cr has 3 unpaired electrons and hence, will be paramagnetic CrH2OCl3

Cr+3=1s2  2s2  2p6 3s2 3p6  3d3 in strong field ligand or weak field ligand is t2g1,1,1,ego



Δ0 order will be compared by spectrochemical series not by energies of violet and yellow light. Hence incorrect

Asked in: JEE Main 2019 (09 Jan Shift 1)

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