The tests performed on compound X and their inferences are :
Test Inference (a) 2, 4 - DNP test Coloured precipitate (b) Idoform test Yellow precipitate (c) Azo-dye test No dye formation
Compound 'X' is :
| Test | Inference | |
| (a) | 2, 4 - DNP test | Coloured precipitate |
| (b) | Idoform test | Yellow precipitate |
| (c) | Azo-dye test | No dye formation |
Compound 'X' is :
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The Correct Option is B
Solution and Explanation
Test (b): the iodoform test is positive (yellow precipitate), so X has a \(\mathrm{CH_3CO-}\) group (methyl ketone) or \(\mathrm{CH_3CH(OH)-}\).
Test (c): no azo dye is formed, so X has no primary aromatic amine (\(\mathrm{ArNH_2}\)).
Option (1) 2-aminophenylacetaldehyde: has \(\mathrm{ArNH_2}\) (azo dye would form) and no \(\mathrm{CH_3CO}\); rejected.
Option (2) 2-(N,N-dimethylamino)acetophenone: has \(\mathrm{COCH_3}\) (DNP and iodoform positive) and a tertiary amine (no azo dye); fits.
Option (3) 1-(2-aminophenyl)ethanol: has \(\mathrm{ArNH_2}\) and no C=O; rejected.
Option (4) 2-(N,N-dimethylamino)phenylacetaldehyde: DNP positive, but no \(\mathrm{COCH_3}\) or \(\mathrm{CH_3CH(OH)}\), so the iodoform test is negative; rejected.
Answer: (2) the ortho-(N,N-dimethylamino)acetophenone structure
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