JEE Main 2024 — Chemistry Inorganic Chemistry

2024mcqeasy

Given below are two statements:

Statement (I): A solution of ${[\mathrm{Ni}{({H}_{2}O)}_{6}]}^{2+}$ is green in colour.

Statement (II): A solution of ${[\mathrm{Ni}(\mathrm{CN}{)}_{4}]}^{2-}$ is colourless.

In the light of the above statements, choose the most appropriate answer from the options given below:

Official previous-year question

Held on 1 Feb 2024 · Verified 6 Jul 2026.

Options

A
Both Statement I and Statement II are incorrect
B
Both Statement I and Statement II are correct
C
Statement I is incorrect but Statement II is correct
D
Statement I is correct but Statement II is incorrect

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Solution

In ${[\mathrm{Ni}{({H}_{2}O)}_{6}]}^{2+}$ , ${H}_{2}O$ is a weak field ligand. Therefore, there are unpaired electrons in ${\mathrm{Ni}}^{2+}$ . In this complex, the d electrons from the lower energy level can be excited to the higher energy level i.e., the possibility of $d-d$ transition is present. Hence, ${[\mathrm{Ni}{({H}_{2}O)}_{6}]}^{2+}$ is coloured.

In ${[\mathrm{Ni}{(\mathrm{CN})}_{4}]}^{2-}$ , the electrons are all paired as ${\mathrm{CN}}^{-}$ is a strong field ligand. Therefore, $d-d$ transition is not possible in ${[\mathrm{Ni}{(\mathrm{CN})}_{4}]}^{2-}$ . Hence, it is colourless.

${[\mathrm{Ni}{({H}_{2}O)}_{6}]}^{+2}\rightarrow$ Green colour solution due to $d-d$ transition.

${[\mathrm{Ni}(\mathrm{CN}{)}_{4}]}^{-2}\rightarrow$ is diamagnetic and it is colourless.

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Solution

${[\mathrm{Ni}{({H}_{2}O)}_{6}]}^{+2}\rightarrow$ Green colour solution due to $d-d$ transition.

${[\mathrm{Ni}(\mathrm{CN}{)}_{4}]}^{-2}\rightarrow$ is diamagnetic and it is colourless.

JEE Main 2024 — Chemistry Inorganic Chemistry

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JEE Main 2024 — 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