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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, - Chemistry

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प्रश्न

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, \[\ce{[Co(NH3)6]^{3+}}\], \[\ce{[Co(CN)6]^{3-}}\], \[\ce{[Co(H2O)6]^{3+}}\]

विकल्प

  • \[\ce{[Co(CN)_6]^{3-} > [Co(NH3)6]^{3+} > [Co(H2O)6]^{3+}}\]

  • \[\ce{[Co(NH3)_6]^{3+} > [Co(H2O)6]^{3+} > [Co(CN)6]^{3-}}\]

  • \[\ce{[Co(H2O)_6]^{3+} > [Co(NH3)6]^{3+} > [Co(CN)6]^{3-}}\]

  • \[\ce{[Co(CN)6]^{3-} > [Co(H2O)6]^{3+} >  [Co(NH3)6]^{3+}}\]

MCQ
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उत्तर

\[\ce{[Co(H2O)_6]^{3+} > [Co(NH3)6]^{3+} > [Co(CN)6]^{3-}}\]

Explanation:

The CFSE of the ligands is in the order:

H2O < NH3 < CN

Hence, excitation energies are in the order:

\[\ce{[Co(H2O)6]^{3+} < [Co(NH3)6]^{3+} < [Co(CN)6]^{3-}}\]

From the relation E = `"hc"/λ` ⇒ `"E" ∝ 1/λ`

The order of absorption of the wavelength of light in the visible region is:

\[\ce{[Co(H2O)_6]^{3+} > [Co(NH3)6]^{3+} > [Co(CN)6]^{3-}}\]

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अध्याय 9: Coordination Compounds - Exercises [पृष्ठ १२०]

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एनसीईआरटी एक्झांप्लर Chemistry [English] Class 12
अध्याय 9 Coordination Compounds
Exercises | Q I. 2. | पृष्ठ १२०

संबंधित प्रश्न

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\[\ce{P4 + H2SO4 ->}\] ______ + ______ + ______


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) \[\ce{[Ni(NH3)6]^{2+}}\]


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):

\[\ce{[Cr(Cl)6]^{3-}, [Cr(CN)6]^{3-}, [Cr(NH3)6]^{3+}}\].


Using crystal field theory, draw energy level diagram, write electronic configuration of the central metal atom/ion and determine the magnetic moment value in the following:

\[\ce{[FeF6]^{3-}, [Fe(H2O)6]^{2+}, [Fe(CN)6]^{4-}}\]


[Ni(H2O)6]2+ (aq) is green in colour whereas [Ni(H2O)4 (en)]2+ (aq)is blue in colour, give reason in support of your answer.


Considering crystal field theory, strong-field ligands such as CN:


The correct order of increasing crystal field strength in following series:


The CFSE of [CoCl6]3– is 18000 cm–1 the CFSE for [CoCl4] will be ______.


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The correct order of intensity of colors of the compounds is ______.


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Read the passage carefully and answer the questions that follow.

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:

Complex Wavenumber of light absorbed (cm-1) Energy of light absorbed (kJ/mol)
[CrA6]3- 13,640 163
[CrB6]3+ 17,830 213
[CrC6]3+ 21,680 259
[CrD6]3- 26,280 314

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:

  1. [CrA6]3-
  2. [CrC6]3+

On the basis of Crystal Field Theory, write the electronic configuration of d4 ion if Δ0 > P.


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