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प्रश्न
State the superiority of crystal field theory over valence bond theory.
उत्तर
Superiority of Crystal Field Theory over Valence Bond Theory:
a) Magnetic properties of complexes and variation with temperature are explained by
crystal field theory. Valence bond theory cannot explain these.
b) Crystal field theory gives the quantitative measure of the stability of complexes. It
predicts the geometry of complexes. It is not possible by valence bond theory
c) Kinetic and thermodynamic properties of some complexes are explained by crystal
field theory but not by valence bond theory.
d) Crystal field theory explains d-d transitions and colour of complexes. This is not
explained by valence bond theory.
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संबंधित प्रश्न
On the basis of crystal field theory, write the electronic configuration for d4 ion if Δ0 > P.
On the basis of crystal field theory, write the electronic configuration for d4 ion if ∆0 < P.
The hexaquo manganese (II) ion contains five unpaired electrons, while the hexacyanoion contains only one unpaired electron. Explain using Crystal Field Theory.
Draw figure to show the splitting of d orbitals in an octahedral crystal field.
What is spectrochemical series? Explain the difference between a weak field ligand and a strong field ligand.
How are the following conversions carried out?
Benzoic acid into metanitrobenzoic acid.
The colour of the coordination compounds depends on the crystal field splitting. What will be the correct order of absorption of wavelength of light in the visible region, for the complexes, \[\ce{[Co(NH3)6]^{3+}}\], \[\ce{[Co(CN)6]^{3-}}\], \[\ce{[Co(H2O)6]^{3+}}\]
The CFSE for octahedral \[\ce{[CoCl6]^{4-}}\] is 18,000 cm–1. The CFSE for tetrahedral \[\ce{[CoCl4]^{2-}}\] will be ______.
Atomic number of \[\ce{Mn}\], \[\ce{Fe}\] and \[\ce{Co}\] are 25, 26 and 27 respectively. Which of the following inner orbital octahedral complex ions are diamagnetic?
(i) \[\ce{[Co(NH3)6]^{3+}}\]
(ii) \[\ce{[Mn(CN)6]^{3-}}\]
(iii) \[\ce{[Fe(CN)6]^{4-}}\]
(iv) \[\ce{[Fe(CN)6]^{3-}}\]
Atomic number of \[\ce{Mn, Fe, Co}\] and Ni are 25, 26, 27 and 28 respectively. Which of the following outer orbital octahedral complexes have same number of unpaired electrons?
(i) \[\ce{[MnCl6]^{3-}}\]
(ii) \[\ce{[FeF6]^{3-}}\]
(iii) \[\ce{[CoF6]^{3-}}\]
(iv) \[\ce{[Ni(NH3)6]^{2+}}\]
Why are low spin tetrahedral complexes not formed?
Give the electronic configuration of the following complexes on the basis of Crystal Field Splitting theory.
\[\ce{[CoF6]^{3-}, [Fe(CN)6]^{4-} and [Cu(NH3)6]^{2+}}\].
Arrange following complex ions in increasing order of crystal field splitting energy (∆O):
\[\ce{[Cr(Cl)6]^{3-}, [Cr(CN)6]^{3-}, [Cr(NH3)6]^{3+}}\].
\[\ce{CuSO4 . 5H2O}\] is blue in colour while \[\ce{CuSO4}\] is colourless. Why?
Why are different colours observed in octahedral and tetrahedral complexes for the same metal and same ligands?
The CFSE for octahedral [CoCl6]−4 is 18,000 cm−1. What will be the CFSE for tetrahedral [CoCl3]−2?
Considering crystal field theory, strong-field ligands such as CN–:
The magnitude of CFSE depends upon ______
What is the spectrochemical series?
The correct order of intensity of colors of the compounds is ______.
For octahedral Mn(II) and tetrahedral Ni(II) complexes, consider the following statements:
(i) Both the complexes can be high spin.
(ii) Ni(II) complex can very rarely below spin.
(iii) With strong field Ligands, Mn(II) complexes can be low spin.
(iv) Aqueous solution of Mn (II) ions is yellow in colour.
The correct statements are:
The complex that has highest crystal field splitting energy (Δ) is ______.
On the basis of Crystal Field theory, write the electronic configuration for the d5 ion with a strong field ligand for which Δ0 > P.
On the basis of crystal field theory, write the electronic configuration for d4 with a strong field ligand for which Δ0 > P.
Read the passage carefully and answer the questions that follow.
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Crystal field splitting by various ligands Metal complexes show different colours due to d-d transitions. The complex absorbs light of specific wavelength to promote the electron from t2g to eg level. The colour of the complex is due to the transmitted light, which is complementary of the colour absorbed. The wave number of light absorbed by different complexes of Cr ion are given below:
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Answer the following questions:
(a) Out of ligands "A", "B", "C" and "D", which ligand causes maximum crystal field splitting? Why?
OR
Which of the two, “A” or “D” will be a weak field ligand? Why?
(b) Which of the complexes will be violet in colour? [CrA6]3- or [CrB6]3+ and why?
(Given: If 560 - 570 nm of light is absorbed, the colour of the complex observed is violet.)
(c) If the ligands attached to Cr3+ ion in the complexes given in the table above are water, cyanide ion, chloride ion, and ammonia (not in this order).
Identify the ligand, write the formula and IUPAC name of the following:
- [CrA6]3-
- [CrC6]3+
