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Question #44142
The Question
Consider an equimolar mixture of 2,4,6-tri-\textit{tert}-butylbenzaldehyde () and formaldehyde (). The mixture is treated with an excess of 50% aqueous at 373 K for several hours. The resulting mixture is then cooled, diluted with water, and carefully acidified with dilute . Which of the following best represents the major organic species present in the final acidified mixture?
Options
- A.
2,4,6-tri-\textit{tert}-butylbenzyl alcohol and formic acid
- B.
2,4,6-tri-\textit{tert}-butylbenzoic acid and methanol
- C.
2,4,6-tri-\textit{tert}-butylbenzaldehyde, methanol, and formic acid
- D.
1,3,5-tri-\textit{tert}-butylbenzene, methanol, and formic acid
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
Disproportionation Constraints|Cannizzaro Mechanism|Nucleophilic Addition Sterics
Why This Question Is Tricky
Common Mistakes
This problem tests the boundary between textbook heuristics and transition state theory.
Students are taught that in a crossed-Cannizzaro reaction with formaldehyde, the formaldehyde is always oxidized while the other non-enolizable aldehyde is reduced.
The trap exploits this heuristic by introducing 2,4,6-tri-tert-butylbenzaldehyde.
While it lacks alpha-hydrogens, its extreme steric hindrance completely blocks the bimolecular hydride transfer (the rate-determining step).
Failing to account for the spatial requirements of the transition state leads students to incorrectly predict the standard crossed-Cannizzaro products, whereas the correct outcome is the kinetic stalling of the cross-reaction and the self-Cannizzaro of formaldehyde.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Redox Reactions - Class 11 Part 2 |
| Concept | Disproportionation Constraints |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |