Coordination Compounds — JEE Advanced · 2020 · 27 Sep 2020 · Paper 2 Question with Solution

In an experiment,

m

grams of a compound X (gas/liquid/solid) taken in a container is loaded in a balance as shown in figure I below. In the presence of a magnetic field, the pan with X is either deflected upwards (figure II), or deflected downwards (figure III), depending on the compound X. Identify the correct statement(s)

(A)If X is $H_{2} O (l)$ , deflection of the pan is upwards.✓ Correct
(B)If X is $K_{4} [Fe (CN)_{6}] (s)$ , deflection of the pan is upwards.✓ Correct
(C)If $X$ is $O_{2} (g)$ , deflection of the pan is downwards.✓ Correct
(D)If X is $C_{6} H_{6} (l)$ , deflection of the pan is downwards.

Answer: (A), (B), (C)

Solution

Paramagnetic substances (with unpaired electrons) are attracted to a magnetic field → pan deflects downwards.

Diamagnetic substances (all electrons paired) are repelled by a magnetic field → pan deflects upwards.

(A)

H_{2} O

— all electrons paired → diamagnetic → upwards ✓

(B)

K_{4} [Fe (CN)_{6}]

—

Fe^{2 +}

with strong field ligand

CN^{-}

→

3 d^{6}

configuration:

[t_{2 g}^{6}, e_{g}^{0}]

→ all paired → diamagnetic → upwards ✓

(C)

O_{2}

— has 2 unpaired electrons in

π^{*}

antibonding orbitals → paramagnetic → downwards ✓

(D)

C_{6} H_{6}

(benzene) — all electrons paired → diamagnetic → upwards (not downwards) ✗

Correct options: (A), (B), (C)

JEE Advanced · 2020 · 27 Sep 2020 · Paper 2 · One or more correct options

JEE Advanced · 2020 · 27 Sep 2020 · Paper 2 · Coordination Compounds

Solution

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