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Question #44367

Difficulty: 8/10 | 🟢 Free

The Question

3,3-dimethylbut-1-ene is treated with excess $D_2O$ in the presence of a catalytic amount of $D_2SO_4$ at 298 K to yield a major product $P$ . Assuming the reaction proceeds via the most stable carbocation intermediate and no reversible alkene formation occurs, determine the number of hyperconjugable $\alpha$ -hydrogens (excluding $\alpha$ -deuterium) in the most stable carbocation intermediate, and the number of chiral centers in $P$ .

Options

A.
7 and 1
B.
7 and 0
C.
2 and 1
D.
6 and 0

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

Acid-Catalyzed Hydration Mechanism|SN1 Carbocation Rearrangement

Why This Question Is Tricky

Common Mistakes

Tests the student's ability to recognize carbocation rearrangements (1,2-methide shift) driven by thermodynamic stability.

The hidden trap lies in the stereochemistry: while the standard hydration of 3,3-dimethylbut-1-ene with $H_2O$ yields an achiral product (2,3-dimethylbutan-2-ol), the use of $D_2O/D^+$ introduces isotopic asymmetry at the terminal carbon.

This breaks the symmetry and makes C3 chiral in the rearranged product, trapping students who rely on memorized structures without tracing the isotopic labels.

Quick Facts About This Question

Question Information

Subject	Chemistry
Chapter	Alcohols, Phenols, and Ethers - Class 12
Concept	Acid-Catalyzed Hydration Mechanism
Difficulty	8
Cognitive Load	7
Target Solve Time	160 sec
Access	Free