For [Fe F _ 6 ] ^ 3 - and [Co F _ 6 ] ^ 3 - , the correct statement is

Correct answer: D. [Fe F _ 6 ] ^ 3 - is colourless and [Co F _ 6 ] ^ 3 - is coloured In [Co F _ 6 ] ^ 3 - it absorbs red colour light so it shows complementary colour green, while in the case of [Fe F _ 6 ] ^ 3 - there is very weak splitting so the light absorbed will be in infrared region so its complementary colour is not in visible region of light hence it appears colourless.

NTA Abhyas 2020

Exam: NTA Abhyas
Year: 2020
Subject: Chemistry
Chapter: Solid State

NTA Abhyas 2020 · Chemistry · Solid State

For [Fe F _ 6 ] ^ 3 - and [Co F _ 6 ] ^ 3 - , the correct statement...

For

{\left[Fe{F}_{6}\right]}^{3 -}

and

{\left[Co{F}_{6}\right]}^{3 -}

, the correct statement is

Options

Aboth are coloured
Bboth are colourless
C ${\left[Fe{F}_{6}\right]}^{3 -}$ is coloured and ${\left[Co{F}_{6}\right]}^{3 -}$ is colourless
D ${\left[Fe{F}_{6}\right]}^{3 -}$ is colourless and ${\left[Co{F}_{6}\right]}^{3 -}$ is coloured

Correct answer

D. ${\left[Fe{F}_{6}\right]}^{3 -}$ is colourless and ${\left[Co{F}_{6}\right]}^{3 -}$ is coloured

Step-by-step solution

{\left[Co{F}_{6}\right]}^{3 -}

it absorbs red colour light so it shows complementary colour green, while in the case of

{\left[Fe{F}_{6}\right]}^{3 -}

there is very weak splitting so the light absorbed will be in infrared region so its complementary colour is not in visible region of light hence it appears colourless.

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