1) Which one of the following complexes shows optical isomerism? A) $cis[Co(en)_{2}Cl_{2}]Cl$ B) $trans[Co(en)_{2}Cl_{2}]Cl$ C) $[Co(NH_{3})_{4}Cl_{2}]Cl$ D) $[Co(NH_{3})_{3}Cl_{3}]$ Answer: Option AExplanation: $[Co(NH_{3})_{4}Cl_{2}]Cl$ can exist both in cis and trans forms that are given below $[Co(NH_{3})_{3}Cl_{3}]$ exists in fac and mer-isomeric forms and both are optically inactive.
