QJEEAdv08Ch0541: JEE Advanced 2008 Chemistry - Class 12 JEEAdv08Ch0541 Solution: Statement 1 : [Fe(H O) NO]SO is paramagnetic. Statement 2 : The …

Question

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Statement 1 : [Fe(H $_2$ O) $_5$ NO]SO $_4$ is paramagnetic.

Statement 2 : The Fe in [Fe(H $_2$ O) $_5$ NO]SO $_4$ has three unpaired electrons.

A Statement 1 is True, Statement 2 is True; Statement 2 is a CORRECT explanation for Statement 1.
B Statement 1 is True, Statement 2 is True; Statement 2 is a NOT CORRECT explanation for Statement 1.
C Statement 1 is True, Statement 2 is False.
D Statement 1 is False, Statement 2 is True.

Accepted Answer

The oxidation state of Fe in the complex, [Fe(H $_2$ O) $_5$ NO]SO $_4$ is +1 [NO has +1 charge]

Fe $^+$ : [Ar] 3d $^+$ 4s $^1$

When the weak ligand H $_2$ O and strong ligand NO attacks, the configuration changes.

NO $^+$ causes pairing of 4s electrons inside. Thus the configuration is 3d $^7$ and number of unpaired electrons = 3.

Fe $^+$ : [Ar] 3d $^7$ 4s $^0$

IIT-JEE 2008 Paper 2 Offline Chemistry - Coordination Compounds Question 11 English Explanation

$\therefore$ Fe $^+$ has 3 unpaired electrons.

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