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Given below are two statements: Statement I: Among [Cu(NH3)4]2+, [Ni(en)3]2+, [Ni(NH3)6]2+ and [Mn(H2O)6]2+, [Mn(H2O)6]2+ has the maximum number of unpaired electrons. Statement II: The number of pairs among {[NiCl4]2−, [Ni(CO)4]}, {[NiCl4]2−, [Ni(CN)4]2−} and {[Ni(CO)4], [Ni(CN)4]2−} that contain only diamagnetic species is two. In the light of the above statements, choose the correct answer from the options given below:

1. Statement I is false but Statement II is true
2. Both Statement I and Statement II are true
3. Both Statement I and Statement II are false
4. Statement I is true but Statement II is false

Correct answer: Statement I is true but Statement II is false

Solution

Statement I is correct because [Mn(H2O)6]2+ has five unpaired electrons due to its high-spin d5 configuration, making it the species with the most unpaired electrons among the given complexes. Statement II is false because only one pair of complexes, [Ni(CO)4] and [Ni(CN)4]2−, are diamagnetic, while the others contain unpaired electrons.

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