NEET UG 2009 — Chemistry Inorganic Chemistry

2009mcqmedium

Out of $\mathrm{TiF}_6^{2-}, \mathrm{CoF}_6^{3-}, \mathrm{Cu}_2 \mathrm{Cl}_2$ and $\mathrm{NiCl}_4^{2-}$ ( $\mathrm{Z}$ of $\mathrm{Ti}=22, \mathrm{Co}=27, \mathrm{Cu}=29, \mathrm{Ni}=28$ ) the colourless species are

Official previous-year question

Held on 30 Apr 2009 · Verified 9 Jul 2026.

Options

A
$\mathrm{TiF}_6^{2-}$ and $\mathrm{CoF}_6^{3-}$
B
$\mathrm{Cu}_2 \mathrm{Cl}_2$ and $\mathrm{NiCl}_4^{2-}$
C
$\mathrm{TiF}_6^{2-}$ and $\mathrm{Cu}_2 \mathrm{Cl}_2$
D
$\mathrm{CoF}_6^{3-}$ and $\mathrm{NiCl}_4^{2-}$

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Solution

Key Idea Species without unpaired electrons are colourless because transition of electron is not passible. (a) In $\mathrm{TiF}_6^{2-}, \mathrm{Ti}$ is present as $\mathrm{Ti}^{4+}$ . $\mathrm{Ti}^{4+}=[\mathrm{Ar}] 3 \mathrm{~d}^0 4 \mathrm{~s}^0$ Hence, $\mathrm{TiF}_6^{2-}$ is colourless. (b) In $\mathrm{CoF}_6^{3-}$ , Co is present as $\mathrm{Co}^{3+}$ NEET 2009 Chemistry, d and f Block Elements — solution figure 1

Due to presence of unpaired electrons, $\mathrm{CoF}_6^{3-}$ is coloured. (c) In $\mathrm{Cu}_2 \mathrm{Cl}_2, \mathrm{Cu}$ is present as $\mathrm{Cu}^{+}$ . NEET 2009 Chemistry, d and f Block Elements — solution figure 2

Due to absence of unpaired electron, $\mathrm{Cu}_2 \mathrm{Cl}_2$ is colourless. (d) In $\mathrm{NiCl}_4^{2-}, \mathrm{Ni}$ is present as $\mathrm{Ni}^{2+}$ . NEET 2009 Chemistry, d and f Block Elements — solution figure 3

Since, unpaired electrons are present, $\mathrm{NiCl}_4^{2-}$ is coloured. Hence, $\mathrm{TiF}_6^{2-}$ and $\mathrm{Cu}_2 \mathrm{Cl}_2$ are colourless species.

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Options

$\mathrm{TiF}_6^{2-}$ and $\mathrm{CoF}_6^{3-}$

$\mathrm{Cu}_2 \mathrm{Cl}_2$ and $\mathrm{NiCl}_4^{2-}$

$\mathrm{TiF}_6^{2-}$ and $\mathrm{Cu}_2 \mathrm{Cl}_2$

$\mathrm{CoF}_6^{3-}$ and $\mathrm{NiCl}_4^{2-}$

Solution

Since, unpaired electrons are present, $\mathrm{NiCl}_4^{2-}$ is coloured. Hence, $\mathrm{TiF}_6^{2-}$ and $\mathrm{Cu}_2 \mathrm{Cl}_2$ are colourless species.

NEET UG 2009 — Chemistry Inorganic Chemistry

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NEET UG 2009 — Chemistry Inorganic Chemistry

Options

Did you get this right?

Solution

Your note

NEET UG Inorganic Chemistry in other years

More NEET UG Inorganic Chemistry questions

Other Chemistry topics for NEET UG

Physical Chemistry

Organic Chemistry

Keep practicing Inorganic Chemistry