Which of the following molecule(s) is/are showing optical isomerism?

Which of the following molecule(s) is/are showing optical isomerism?
  1. \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}ight)_{3} light]^{\oplus}\)
  2. \(\left[\mathrm{Co}(\mathrm{en})\left(\mathrm{NH}_{3}ight)_{2}ight]^{2+}\)
  3. \(\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}ight)_{4}(\mathrm{en})ight]^{3+}\)
  4. \(\left[\mathrm{Co}(\mathrm{en})_{2}\left(\mathrm{NH}_{3}ight)_{2}ight]^{3+}\)

Solution

Optical isomerism is shown by:
(i) complexes of the type \(\left[M(A A) X_{2} Y_{2}ight]\) containing one symmetrical bidentate ligand.
(ii) complexes of the type \(\left[M(A A)_{3}ight]\)
containing a symmetrical bidentate ligand.
(iii) complexes of the type \(\left[M(A A)_{2} X_{2}ight]\)
So, from the given option, only \(\left[\mathrm{Co}(\mathrm{en})_{2}\left(\mathrm{NH}_{3}ight)_{2}ight]^{3+}\)
Shows optical isomerism and the others doesn't.

Asked in: JEE-TOPICTESTS-CHEMISTRY

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