1)

Which one of the following has an optical isomer?

(en = ethylenediamine)


A) $\left[Zn(en) (NH_{3})_{2}\right]^{2+}$

B) $\left[Co(en)_{3}\right]^{3+}$

C) $\left[Co(H_{2}O)_{4}(en)\right]^{3+}$

D) $\left[Zn(en)_{2}\right]^{2+}$

Answer:

Option B

Explanation:

Option (b) shows optical isomerism

$\left[Co(en)_{3}\right]^{3+}$

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Complexes of Zn++ cannot show optical isomerism as they are tetrahedral complexes with plane of symmetry

$\left[Co(H_{2}O)_{4}(en)\right]^{3+}$have two planes of symmetry hence it is also optically inactive.

$\left[Zn(en)_{2}\right]^{2+}$cannot show optical isomerism