Which of the following does not show optical isomerism? (en = ethylenediamine)
- [Co(NH3)3Cl3]0
- [Co(en)Cl2(NH3)2]+
- [Co(en)3]3+
- [Co(en)2Cl2]+
Answer
(1) [Co(NH3)3Cl3]0
Solution
[Co(NH3)3Cl3] ([Ma3b3] type) exists only as fac and mer isomers; both have a plane of symmetry optically inactive.
[Co(en)Cl2(NH3)2]+: the isomer with both Cl cis and both NH3 cis is chiral optically active form exists.
[Co(en)3]3+: as per NCERT, exists as d and l forms.
[Co(en)2Cl2]+: as per NCERT, the cis isomer is optically active.
Answer: (1)