JEE Main 2022 · 26 Jul · Shift 2 · Chemistry Q71

ChemistrySingle correct+4 / -1Question 71 of 90

The metal complex that is diamagnetic is (Atomic number: Fe, 26; Cu, 29)

\mathrm{K_3[Cu(CN)_4]}

\mathrm{K_2[Cu(CN)_4]}

\mathrm{K_3[Fe(CN)_4]}

\mathrm{K_4[FeCl_6]}

Answer and worked solution

Official answer: A

$\mathrm{K_3[Cu(CN)_4]}$ : Cu(I) is $3d^{10}$ , with no unpaired electrons.

Cu(II) in B is $d^9$ ; the iron complexes in C and D have unpaired electrons.

(A)

Topics:Magnetic properties and colour Valence bond theory

JEE Main 2022 · 26 Jul · Shift 2, Chemistry question 71