Asserțion : `[Fe(H_2O)_5 NO]SO_4` is paramagnetic.
Reason : The Fe in `[Fe(H_2O)_5NO]SO_4` has three unpaired electrons.

Options

A. If both (A) and (R) are correct and (R) is the correct explanation of (A).
B. If both (A) and (R) are correct, but (R) is not the correct explanation of (A).
C. If (A) is correct, but(R) is incorrect.
D. If both (A) and (R) are.incorrect.

Answer

A

Explanation

`[Fe(H_2O)_5 NO] SO_4`
NO has charge equal to +1 in this complex. Therefore, the oxidation number of Fe.in the complex becomes +1.
`Fe = 3d^6 4s^2 , Fe^(o+) = 3d^6 4s^1`

After pairing

Since `H_2O` is a weak field ligand and `NO^(o+)` is a strong field ligand, so only `NO^(o+)` causes pairing of 4s electron. Thus only one pairing occurs.
Thus, the configuration is `3ď^7` and the number of unpaired electrons is 3.