Three complexes, [CoCl(NH_{3})_{5}]^{2+} (I)[Co(NH_{3})_{5}H_{2}O]^{3+} (II) and 

[Co(NH_{3})_{6}]^{3+} (III) absorb light in the visible region.

The correct order of the wavelength of light absorbed by them is:

  • Option 1)

    (III) > (I) > (II)

  • Option 2)

    (III) > (II) > (I)

  • Option 3)

    (II) > (I) > (III)

  • Option 4)

    (I) > (II) > (III)

Answers (1)

The strength of ligands follows the given order :

Cl^{-}<H_{2}O<NH_{3}

\therefore NH_{3} is the strongest ligand, thus more energy will be absorbed by it.

Thus, lesser wavelength of light it will absorb, because energy is invesely 

propotional to wavelength.

E\propto \frac{1}{\lambda}

\therefore [CoCl(NH_{3})_{5}]^{2+} will absorb the highest wavelength of light.

\therefore correct option is (4)

(I) > (II) > (III)


Option 1)

(III) > (I) > (II)

Option 2)

(III) > (II) > (I)

Option 3)

(II) > (I) > (III)

Option 4)

(I) > (II) > (III)

Exams
Articles
Questions