Question
Two complexes $$\left[ {Cr\left( {{H_2}{O_6}} \right)} \right]C{l_3}\left( A \right)\,{\text{and}}\,\left[ {Cr{{\left( {N{H_3}} \right)}_6}} \right]C{l_3}\left( B \right)$$ are violet and yellow coloured, respectively. The incorrect statement regarding them is:
A.
values of $$\left( A \right)\,{\text{and}}\,\left( B \right)$$ are calculated from the energies of biolet and yellow light, respectively.
values of $$\left( A \right)\,{\text{and}}\,\left( B \right)$$ are calculated from the energies of biolet and yellow light, respectively.
B.
both are paramagnetic with three unpaired electrons.
C.
both absorb energies corresponding to their complementary colors.
D.
value for $$\left( A \right)$$ is less than that $$\left( B \right).$$
value for $$\left( A \right)$$ is less than that $$\left( B \right).$$
Answer :
values of $$\left( A \right)\,{\text{and}}\,\left( B \right)$$ are calculated from the energies of biolet and yellow light, respectively.
values of $$\left( A \right)\,{\text{and}}\,\left( B \right)$$ are calculated from the energies of biolet and yellow light, respectively. Solution :
$$E.C.\,{\text{of}}\,C{r^{3 + }}\left( {3{d^3}} \right):$$
For complex A $${\left[ {Cr{{\left( {{H_2}O} \right)}_2}} \right]^{3 + }}:$$
.PNG "Co-ordination Compounds mcq solution image")
For complex B $${\left[ {Cr{{\left( {N{H_3}} \right)}_6}} \right]^{3 + }}:$$
.PNG "Co-ordination Compounds mcq solution image")
Here, both the complexes $$\left( A \right)\,{\text{and}}\,\left( B \right)$$ are paramagnetic with $$3$$ unpaired electrons each. Also $$H2O$$ is a weak field ligand which causes lesser splitting than NH3 which is comparatively stronger field ligand. Hence, the $$\left( {D0} \right)$$ value of $$\left( A \right)\,{\text{and}}\,\left( B \right)$$ are calculated from the wavelengths of light absorbed and not from the wavelengths of light emitted.
$$E.C.\,{\text{of}}\,C{r^{3 + }}\left( {3{d^3}} \right):$$
For complex A $${\left[ {Cr{{\left( {{H_2}O} \right)}_2}} \right]^{3 + }}:$$
For complex B $${\left[ {Cr{{\left( {N{H_3}} \right)}_6}} \right]^{3 + }}:$$
Here, both the complexes $$\left( A \right)\,{\text{and}}\,\left( B \right)$$ are paramagnetic with $$3$$ unpaired electrons each. Also $$H2O$$ is a weak field ligand which causes lesser splitting than NH3 which is comparatively stronger field ligand. Hence, the $$\left( {D0} \right)$$ value of $$\left( A \right)\,{\text{and}}\,\left( B \right)$$ are calculated from the wavelengths of light absorbed and not from the wavelengths of light emitted.