Which one of the following complex ions has geometrical isomers?

• Correct answer
  A

  $\left[\mathrm{Co}(\mathrm{Cl})_2(\mathrm{en})_2\right]^{+}$
• B

  $\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_4(\mathrm{en})\right]^{3+}$
• C

  $\left[\mathrm{Co}(\mathrm{en})_3\right]^{3+}$
• D

  $\left[\mathrm{Ni}\left(\mathrm{NH}_3\right)_5 \mathrm{Br}\right]^{+}$

Solution

So, $\left[\mathrm{Co}(\mathrm{Cl})_2,(\mathrm{en})_2\right]^{+}$have cis and trans isomers hence it show geometrical isomersism.

Hence, the correct answer is option: 'A'.