AIIMS 2010 Chemistry Hydrazones and their formation MCQ Question
Compound A (molecular formula C₃H₆O) is treated with acidified potassium dichromate to form a product B (molecular formula C₃H₆O). B forms a shining silver mirror on warming with ammoniacal silver nitrate. B when treated with an aqueous solution of H₂NCONHNH₂, HCl and sodium acetate gives a product C. Identify the structure of C.
CH₃CH₂CH = NNHCONH₂
CH₃ - C ≡ NNHCONH₂
CH₃ - C ≡ NCONHNH₂
CH₃CH₂CH = NCONHNH₂
Correct Answer
Detailed Explanation
Compound A with the molecular formula C₃H₆O is likely an aldehyde or a ketone. When treated with acidified potassium dichromate, it undergoes oxidation. The product B retains the same molecular formula C₃H₆O, indicating that it is a ketone, as aldehydes would be oxidized to carboxylic acids. The formation of a shining silver mirror with ammoniacal silver nitrate suggests that B is a reducing sugar or an aldehyde, but since it is confirmed as a ketone, it must be a specific structure that can undergo this reaction under certain conditions. The treatment of B with H₂NCONHNH₂, HCl, and sodium acetate indicates a reaction involving hydrazine, leading to the formation of a hydrazone. Among the options, A (CH₃CH₂CH = NNHCONH₂) is the correct structure for product C, as it represents a hydrazone formed from a ketone. The other options do not fit the expected structure of a hydrazone derived from the ketone B. Option B (CH₃ - C ≡ NNHCONH₂) suggests an incorrect structure with a triple bond, while C (CH₃ - C ≡ NCONHNH₂) and D (CH₃CH₂CH = NCONHNH₂) do not correctly represent the product of the reaction described.
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