The correct order of the calculated… - JEE Main 2020 Chemistry PYQ

JEE Main 2020 — Chemistry Organic Chemistry

2020mcqmedium

The correct order of the calculated spin-only magnetic moments of complexes $(A)$ to $(D)$ is:

$(A)$ $Ni{(CO)}_{4}$

$(B)$ $[Ni{({H}_{2}O)}_{6}]C{l}_{2}$

$(C)$ $N{a}_{2}[Ni{(CN)}_{4}]$

$(D)$ $PdC{l}_{2}{(PP{h}_{3})}_{2}$

Official previous-year question

Held on 8 Jan 2020 · Verified 6 Jul 2026.

Options

A
$(A)\approx (C)<(B)\approx (D)$
B
$(C)<(D)<(B)<(A)$
C
$(C)\approx (D)<(B)<(A)$
D
$(A)\approx (C)\approx (D)<(B)$

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Solution

$[Pd{(PP{h}_{3})}_{2}C{l}_{2}],P{d}^{2+}=4{d}^{8},M=0$

$[Ni{(CO)}_{4}],Ni=3{d}^{8}4{s}^{2}(SFL),M=0$

${[Ni{(CN)}_{4}]}^{2-}$ $N{i}^{2+}=3{d}^{8}(SFL)$ $M=0$

${[Ni{({H}_{2}O)}_{6}]}^{2+}$ $N{i}^{2+}=3{d}^{8}(WFL)$ ${t}_{2g}^{2, 2, 2},{e}_{g}^{1, 1}$ So, unpaired electron is $2,M=\sqrt{8}BM$

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