Question

Which of the following statements below is false regarding the complex ion [co(en)2(h2o)cn]2+ ? -The complex ion contains Co(I).

-The complex ion exhibits cis and trans geometric isomers, but no optical isomers.
-The complex ion exhibits two geometric isomers (cis and trans) and two optical isomers.
- The geometric isomers of the complex ion have identical chemical properties.
- Because en is a strong field ligand (large Δ), the complex ion is paramagnetic.

Answer 1

All of the statements are true except for the last one.

The complex ion [co(en)2(h2o)cn]2+ does contain Co(I).
The complex ion does exhibit cis and trans geometric isomers, but no optical isomers.
The complex ion does exhibit two geometric isomers (cis and trans) and two optical isomers.
The geometric isomers of the complex ion do have identical chemical properties.
However, the statement "Because en is a strong field ligand (large Δ), the complex ion is paramagnetic." is false. The complex ion is actually diamagnetic because it has no unpaired electrons. The fact that en is a strong field ligand does not affect the magnetic properties of the complex ion.