JEE Main 2021 — Chemistry Inorganic Chemistry

2021mcqhard

Which one of the following species responds to an external magnetic field?

Official previous-year question

Held on 25 Jul 2021 · Verified 6 Jul 2026.

Options

A
${[\mathrm{Fe}{({H}_{2}O)}_{6}]}^{3+}$
B
${[\mathrm{Ni}{(\mathrm{CN})}_{4}]}^{2-}$
C
${[\mathrm{Co}{(\mathrm{CN})}_{6}]}^{3-}$
D
$[\mathrm{Ni}{(\mathrm{CO})}_{4}]$

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Solution

${[\mathrm{Fe}{({H}_{2}O)}_{6}]}^{3+}$

${\mathrm{Fe}}^{3+}:[\mathrm{Ar}]3{d}^{5}$

Hybridisation : ${\mathrm{sp}}^{3}{d}^{2}$

Magnetic nature : Paramagnetic (so this complex response to external magnetic field)

${[\mathrm{Ni}{(\mathrm{CN})}_{4}]}^{2-}$

${\mathrm{Ni}}^{3+}:[\mathrm{Ar}]3{d}^{8}$

Hybridisation : ${\mathrm{dsp}}^{2}$

Magnetic nature : diamagnetic

${[\mathrm{Co}{(\mathrm{CN})}_{6}]}^{3-}$

${\mathrm{Co}}^{3+}:[\mathrm{Ar}]3{d}^{6}$

Hybridisation : ${d}^{2}{\mathrm{sp}}^{3}$

Magnetic nature : diamagnetic

$[\mathrm{Ni}{(\mathrm{CO})}_{4}]$

$\mathrm{Ni}:[\mathrm{Ar}]3{d}^{8}4{s}^{2}$

Hybridisation : ${\mathrm{sp}}^{3}$

Magnetic nature : diamagnetic

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JEE Main Inorganic Chemistry in other years

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JEE Main 2021 — Chemistry Inorganic Chemistry

2021mcqhard

Which one of the following species responds to an external magnetic field?

Official previous-year question

Held on 25 Jul 2021 · Verified 6 Jul 2026.

Options

A
${[\mathrm{Fe}{({H}_{2}O)}_{6}]}^{3+}$
B
${[\mathrm{Ni}{(\mathrm{CN})}_{4}]}^{2-}$
C
${[\mathrm{Co}{(\mathrm{CN})}_{6}]}^{3-}$
D
$[\mathrm{Ni}{(\mathrm{CO})}_{4}]$

Did you get this right?

Solution

${[\mathrm{Fe}{({H}_{2}O)}_{6}]}^{3+}$

${\mathrm{Fe}}^{3+}:[\mathrm{Ar}]3{d}^{5}$

Hybridisation : ${\mathrm{sp}}^{3}{d}^{2}$

Magnetic nature : Paramagnetic (so this complex response to external magnetic field)

${[\mathrm{Ni}{(\mathrm{CN})}_{4}]}^{2-}$

${\mathrm{Ni}}^{3+}:[\mathrm{Ar}]3{d}^{8}$

Hybridisation : ${\mathrm{dsp}}^{2}$

Magnetic nature : diamagnetic

${[\mathrm{Co}{(\mathrm{CN})}_{6}]}^{3-}$

${\mathrm{Co}}^{3+}:[\mathrm{Ar}]3{d}^{6}$

Hybridisation : ${d}^{2}{\mathrm{sp}}^{3}$

Magnetic nature : diamagnetic

$[\mathrm{Ni}{(\mathrm{CO})}_{4}]$

$\mathrm{Ni}:[\mathrm{Ar}]3{d}^{8}4{s}^{2}$

Hybridisation : ${\mathrm{sp}}^{3}$

Magnetic nature : diamagnetic

Your note

JEE Main Inorganic Chemistry in other years

Keep practicing Inorganic Chemistry

Work through every JEE Main Inorganic Chemistry PYQ, year by year.

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JEE Main 2021 — Chemistry Inorganic Chemistry

Options

Did you get this right?

Solution

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JEE Main Inorganic Chemistry in other years

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Other Chemistry topics for JEE Main

Physical Chemistry

Organic Chemistry

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JEE Main 2021 — Chemistry Inorganic Chemistry

Options

Did you get this right?

Solution

Your note

JEE Main Inorganic Chemistry in other years

More JEE Main Inorganic Chemistry questions

Other Chemistry topics for JEE Main

Physical Chemistry

Organic Chemistry

Keep practicing Inorganic Chemistry