Question

Which one of the following complexes shows optical isomerism? (en = ethylenediamine)

Options

• [Co(NH₃)₃Cl₃]

• cis[Co(en)₂Cl₂]Cl

• trans[Co(en)₂Cl₂]Cl

• [Co(NH₃)₄Cl₂]Cl

Answer 1

cis[Co(en)₂Cl₂]Cl

Explanation:

• Optical isomerism occurs in chiral complexes that have non-superimposable mirror images.
• cis[Co(en)₂Cl₂]⁺ has two bidentate en ligands in a cis arrangement, making it chiral.
• The trans isomer and complexes with only monodentate ligands are achiral and do not show optical isomerism.