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Question #44173

Difficulty: 8/10 | 🟢 Free

The Question

Consider the following reaction sequence starting from trichloroacetaldehyde (A) at 298 K:

$\ce{CCl3CHO + H2O <=> B}$ (A stable, crystalline gem-diol)
$\ce{B + NaOH(aq) -> C}$ (dense liquid) + $\ce{D}$ (water-soluble salt) + $\ce{H2O}$
$\ce{C + Ph-NH2 + 3KOH ->[\Delta] E}$ (foul-smelling compound) + $\ce{3KCl + 3H2O}$

Compound B exhibits exceptional thermodynamic stability for a gem-diol. Its central $sp^3$ carbon experiences a non-standard O-C-O bond angle distortion driven by the $-I$ effect of the adjacent group and the formation of intramolecular pseudo-rings.

Determine the value of the expression: $\frac{(P^2 \times S) + (Q^3 \times R)}{P}$

Where: $P$ = Number of intramolecular hydrogen bonds in a single molecule of B in its most stable conformation. $Q$ = Oxidation state of the carbon atom in compound C. $R$ = Total number of $\pi$ -bonds in one molecule of compound E. $S$ = Number of atoms in one pseudo-ring formed by the intramolecular hydrogen bonding in B.

Options

A.
26
B.
30
C.
45
D.
170

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

Hybridization in Non-Standard Cases|Hydrate Stability vs. Carbonyl|Resonance Stability Criteria

Why This Question Is Tricky

Common Mistakes

The question tests the 'Chemical Exception' of gem-diol stability.

Normally, gem-diols are unstable due to steric and lone-pair repulsion, favoring the carbonyl form.

However, in chloral hydrate, the extreme electron-withdrawing nature of the $\ce{-CCl3}$ group and the formation of a specific geometry locked by intramolecular hydrogen bonding (forming 5-membered chelate rings) reverses this thermodynamic preference.

Students often fail to account for the exact structural parameters of this non-standard $sp^3$ geometry (number of H-bonds and ring size).

Furthermore, it integrates this structural anomaly with classic reaction mechanisms (Haloform cleavage of a hydrate and the Carbylamine reaction) and redox state calculations, creating a multi-layered trap.

Quick Facts About This Question

Question Information

Subject	Chemistry
Chapter	Chemical Bonding and Molecular Structure - Class 11 Part 1
Concept	Hybridization in Non-Standard Cases
Difficulty	8
Cognitive Load	7
Target Solve Time	160 sec
Access	Free