Question

(a). Assertion (A) is true, Reason (R) is also true, Reason (R) is the correct explanation for assertion (A).
(b). Assertion (A) is true, Reason (R) is true, Reason (R) is not the correct explanation for Assertion (A).
(c). Assertion (A) is true, Reason (R) is false.
(d). Assertion (A) is false, Reason (R) is true.
Q. Assertion (A): `[Fe(H_2O)_5NO]SO_4` paramagnetic.
Reason (R): The Fe in `[Fe(H_2O)_5NO]SO_4` has three unpaired electrons.

Answer 1

Correct Answer - A
`[Fe(H_2O)_5NO]SO_4`
NO has charge equal to `+1`. Therefore,t he oxidation number complex becomes `+1`.
`Fe=3d^64s^2`
`Fe^(o+)=3d^64s^1`
`H_2O` is a weak field ligand and `NO^(o+)` is a strong firld ligand, hence only one pairing occurs.
Thus, the configuration is `3d^7` and the number of unpaired electrons is 3.