Ncert Exercises & Solutions

Given below are two statements:

Assertion (A):	$[C r (H_{2} O_{6})] C l_{2}$ and $[F e {(H_{2} O)}_{6}] C l_{2}$ are reducing in nature.
Reason (R):	Unpaired electrons are present in their d-orbitals.

1.	Both (A) and (R) are True, and (R) is the correct explanation of (A).
2.	Both (A) and (R) are True, and (R) is not the correct explanation of (A).
3.	(A) is true, but the (R) is False.
4.	(A) is False, but (R) is True.

Hint: Both can show a +3 oxidation state.

Explanation:

Assertion (A): [Cr(H₂O)₆]Cl₂ and [Fe(H₂O)₆]Cl₂ are reducing in nature. This is true as Cr²⁺ (3d⁴) and Fe²⁺ (3d⁶) can be oxidized to more stable Cr³⁺ and Fe³⁺ states.
Reason (R): Unpaired electrons are present in their d-orbitals. This is true as Cr²⁺ has 4 and Fe²⁺ has 4 unpaired electrons.
Relationship: Both are true, but the Reason (unpaired electrons) is not the complete explanation for the reducing nature, which depends on oxidation state stability.