JEE Main 2026 Jan 21 Shift 1, Chemistry Q15: Colour, Magnetism And Stability Of Co-ordination Compounds

JEE Main2026Jan 21, Shift 1Chemistry

Given below are two statements:

Statement I: Among $[C u (N H_{3})_{4}]^{2 +}, [N i (e n)_{3}]^{2 +}, [N i (N H_{3})_{6}]^{2 +}$ and $[M n (H_{2} O)_{6}]^{2 +}$ , $[M n (H_{2} O)_{6}]^{2 +}$ has the maximum number of unpaired electrons.

Statement II: The number of pairs among ${[N i C l_{4}]^{2 -}, [N i (C O)_{4}]}, {[N i C l_{4}]^{2 -}, [N i (C N)_{4}]^{2 -}}$ and ${[N i (C O)_{4}], [N i (C N)_{4}]^{2 -}}$ that contain only diamagnetic species is two.

In the light of the above statements, choose the correct answer from the options given below:

A
Statement I is false but Statement II is true
B
Both Statement I and Statement II are true
C
Both Statement I and Statement II are false
D
Statement I is true but Statement II is false

Solution

Unpaired electrons: $[C u (N H_{3})_{4}]^{2 +} \to$ 1, $[N i (e n)_{3}]^{2 +} \to$ 2, $[N i (N H_{3})_{6}]^{2 +} \to$ 2, $[M n (H_{2} O)_{6}]^{2 +} \to$ 5. Statement I true.

$[N i (C O)_{4}]$ and $[N i (C N)_{4}]^{2 -}$ are diamagnetic; $[N i C l_{4}]^{2 -}$ is paramagnetic. Only one pair has both diamagnetic. Statement II false.

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JEE Main 2026 Jan 21 Shift 1, Chemistry Q15: Colour, Magnetism And Stability Of Co-ordination Compounds

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