Question

Assertion: The $\left[ Ni ( en )_{3} Cl _{2}\right] Cl _{2}$ (en = ethylene diamine) has lower stability than $\left[ Ni \left( NH _{3}\right)_{6} Cl _{2}\right]$.
Reason : In $\left[ Ni ( en )_{3} Cl _{2}\right]$ the geometry of $Ni$ is trigonal bipyramidal.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (D)

In $\left[ Ni ( en )_{3}\right] Cl _{2}$, ethylene diamine $( en )$ is a bidentate ligand, hence it forms chelating ring with $Ni ^{2+}$ ion. Chelates are comparatively more stable. Hence, $\left[ Ni ( en )_{3}\right] Cl _{2}$ is more stable than $\left[ Ni \left( NH _{3}\right)_{6}\right] Cl _{2}$.