Before You Begin

Question #44295

Difficulty: 8/10 | 🟢 Free

The Question

Consider the following four gas-phase charge-transfer equilibria established in a reactor at $298\text{ K}$ . Assume the standard entropy change ( $\Delta S^\circ$ ) for each reaction is negligible ( $\Delta S^\circ \approx 0$ ).

(I) $\ce{O(g) + N+(g) <=> O+(g) + N(g)}$ ( $K_I$ ) (II) $\ce{Cr(g) + Mn+(g) <=> Cr+(g) + Mn(g)}$ ( $K_{II}$ ) (III) $\ce{Cr+(g) + Mn^2+(g) <=> Cr^2+(g) + Mn+(g)}$ ( $K_{III}$ ) (IV) $\ce{N+(g) + O^2+(g) <=> N^2+(g) + O+(g)}$ ( $K_{IV}$ )

Let $l_I, l_{II}, l_{III},$ and $l_{IV}$ be the azimuthal quantum numbers of the specific orbitals from which the electron is extracted from the reducing agent in the forward direction of reactions I, II, III, and IV, respectively.

Which of the following options correctly identifies the conditions for the equilibrium constants (relative to 1) and the exact sequence of azimuthal quantum numbers $(l_I, l_{II}, l_{III}, l_{IV})$ ?

Options

A.
$K_I > 1,\; K_{II} > 1,\; K_{III} < 1,\; K_{IV} > 1$ and $(1, 0, 2, 1)$
B.
$K_I < 1,\; K_{II} < 1,\; K_{III} > 1,\; K_{IV} < 1$ and $(1, 2, 0, 1)$
C.
$K_I > 1,\; K_{II} > 1,\; K_{III} > 1,\; K_{IV} < 1$ and $(1, 0, 0, 1)$
D.
$K_I > 1,\; K_{II} < 1,\; K_{III} < 1,\; K_{IV} < 1$ and $(1, 2, 2, 1)$

Check Your Answer

Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Exception_Exposure

Learn to identify edge cases and boundary exceptions that JEE examiners hide in math problems.

Concepts Behind This Question

Ionization Enthalpy (IE) Anomalies|Aufbau Principle Exceptions|Electron Transfer Accounting

Why This Question Is Tricky

Common Mistakes

This problem tests the precise accounting of electrons during successive ionizations of elements with anomalous electronic configurations (Cr) and standard p-block anomalies (N vs O).

The core trap lies in Reaction III: students often incorrectly assume $\ce{Cr+}$ retains a $4s$ electron (like $4s^1 3d^4$ ) or that the 'anomalous' $3d$ electron is removed first in Reaction II.

By forcing the identification of the azimuthal quantum number ( $l$ ) of the extracted electron, the problem exposes whether the student truly understands that $ns$ electrons are removed before $(n-1)d$ electrons, and that $\ce{Cr+}$ is exactly $3d^5$ , making its second ionization enthalpy exceptionally high compared to Mn.

Quick Facts About This Question

Question Information

Subject	Chemistry
Chapter	Classification of Elements and Periodicity in Properties - Class 11 Part 1
Concept	Ionization Enthalpy (IE) Anomalies
Difficulty	8
Cognitive Load	7
Target Solve Time	160 sec
Access	Free