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Question #44433
The Question
An optically active compound () is treated with exactly one equivalent of periodic acid () at 298 K to yield two moles of a single compound . Compound gives a positive Tollens' test (silver mirror) but fails to produce a red precipitate when heated with Fehling's solution. Instead, the strongly basic conditions of Fehling's solution cause to undergo a rapid rearrangement to an intermediate that, upon careful acidification, yields compound . Let be the number of hybridized carbon atoms and be the number of hybridized carbon atoms in a single molecule of . What is the value of ?
Options
- A.
5
- B.
6
- C.
7
- D.
8
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
Glycol Periodic Acid Cleavage|Tollens vs. Fehling Specificity
Why This Question Is Tricky
Common Mistakes
Tests the chemoselectivity of HIO4 cleavage (vicinal diol vs alpha-hydroxy ketone) and the specific reactivity of alpha-keto aldehydes.
Students often falsely assume all aldehydes reduce Fehling's solution or that failure is solely due to aromaticity.
The hidden variable is the strong base in Fehling's solution, which triggers a rapid internal Cannizzaro rearrangement of phenylglyoxal into mandelic acid, outcompeting the oxidation process.
Quick Facts About This Question
Question Information
| Subject | Chemistry |
| Chapter | Alcohols, Phenols, and Ethers - Class 12 |
| Concept | Glycol Periodic Acid Cleavage |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |