Question

Which of the following statements is not true about the complex ion $\left[CrCl\right(N{O}_2\left)\right(en{)}_2{]}^{+}$?

• A. It has two geometrical isomers cis and trans
• B. Cis and trans forms are not diastereomers to each other
• C. Only the cis isomers displays optical activity
• D. It has three optically active isomers: $d,l$ and trans forms

Answer 1

Answer: (B), (D)

Cis and trans forms are not diastereomers to each other
It has three optically active isomers: $d,l$ and trans forms

(A) Two geometrical isomers are possible for the complex $\left[CrCl\right(N{O}_2\left)\right(en{)}_2{]}^{+}$ cis and trans.
In the cis isomer, two ethylene diamine ligands are adjacent and in the trans isomer, they are opposite.
Thus statement A is true.
(B) Cis and trans forms are diastereomers to each other.
Thus statement B is not true.
(C) Only the cis isomers display optical activity. Whereas trans isomer is optically inactive.
Thus statement C is true.
(D) Cis isomer has two optically active isomers: d, l form. The trans form is optically inactive.
Thus statement D is not true.

Hence, the correct options are $\text{B}$ and $\text{D}$