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Question #44598

Difficulty: 8/10 | 🟢 Free

The Question

Consider the 'brown ring' complex $X$ formed during the nitrate ring test, and the nitroprusside anion $Y$ used for the detection of sulfide ions. Which of the following correctly lists the oxidation state of Iron, the Effective Atomic Number (EAN) of Iron, and the spin-only magnetic moment ( $\mu_{eff}$ ) for complex $X$ and complex $Y$ , respectively?

Options

A.
$X$ : +1, 37, 3.87 BM ; $Y$ : +2, 36, 0 BM
B.
$X$ : +2, 36, 4.90 BM ; $Y$ : +3, 35, 1.73 BM
C.
$X$ : +1, 37, 3.87 BM ; $Y$ : +3, 35, 1.73 BM
D.
$X$ : +2, 37, 4.90 BM ; $Y$ : +2, 36, 0 BM

Check Your Answer

Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Mechanism_Trap

Don't get tricked by the process! Learn the mechanical traps used in competitive exam questions.

Concepts Behind This Question

EAN Rule (Sidgwick's Rule)|Oxidation State Traps|Valence Bond Theory Hybridization

Why This Question Is Tricky

Common Mistakes

The question tests the anomalous oxidation state of Iron in nitrosyl complexes.

Students frequently misassign the oxidation state of NO as neutral (0) or anionic (-1), leading to incorrect oxidation states for Fe (+2 or +3).

Recognizing NO as the nitrosonium cation (\ce{NO+}) is the key hidden variable.

Furthermore, the brown ring complex is a classic exception to the 18-electron (or EAN) rule, possessing 37 electrons, which traps students who blindly force the EAN to 36.

Quick Facts About This Question

Question Information

Subject	Chemistry
Chapter	Coordination Compounds - Class 12
Concept	EAN Rule (Sidgwick's Rule)
Difficulty	8
Cognitive Load	7
Target Solve Time	160 sec
Access	Free