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NEET 2026
Exam
NEET
Year
2026
Subject
Chemistry
Chapter
Chapter

NEET 2026 · Chemistry · Chapter

Consider the organic molecule provided in the figure. It is...

Consider the organic molecule provided in the figure. It is subjected to the following reaction sequence: 1. LiAlH_4 in
Consider the organic molecule provided in the figure. It is subjected to the following reaction sequence:

1. LiAlH4LiAlH_4 in ether, followed by H2OH_2O
2. NaNO2NaNO_2 and HClHCl at 273−278273-278 K
3. Warming with H2OH_2O

Identify the major organic product formed at the end of this sequence.

Options

  1. ABu\tan^{-1}-ol
  2. BPen\tan^{-1}-ol
  3. CPentanoic acid
  4. DPentanenitrile

Correct answer

B. Pen\tan^{-1}-ol

Step-by-step solution

The given starting material is pentanamide, which has a 5-carbon chain: CH3CH2CH2CH2CONH2CH_3CH_2CH_2CH_2CONH_2.

Reaction with LiAlH4LiAlH_4 in ether followed by H2OH_2O reduces the amide to a primary amine. The carbonyl group (−C=O-C=O) is converted to a methylene group (−CH2−-CH_2-).
CH3CH2CH2CH2CONH2→LiAlH4CH3CH2CH2CH2CH2NH2CH_3CH_2CH_2CH_2CONH_2 \xrightarrow{LiAlH_4} CH_3CH_2CH_2CH_2CH_2NH_2

Reaction of the resulting primary aliphatic amine (pen\tan^{-1}-amine) with NaNO2NaNO_2 and HClHCl at 273−278273-278 K generates nitrous acid (HNO2HNO_2), which forms an unstable aliphatic diazonium salt.
CH3(CH2)4NH2→NaNO2,HCl[CH3(CH2)4N2+Cl−]CH_3(CH_2)_4NH_2 \xrightarrow{NaNO_2, HCl} [CH_3(CH_2)_4N_2^+Cl^-]

Warming this diazonium salt with water causes it to decompose, releasing nitrogen gas and forming the corresponding primary alcohol.
[CH3(CH2)4N2+Cl−]→H2O,ΔCH3(CH2)4OH+N2+HCl[CH_3(CH_2)_4N_2^+Cl^-] \xrightarrow{H_2O, \Delta} CH_3(CH_2)_4OH + N_2 + HCl

The final major organic product is pen\tan^{-1}-ol.

Answer: Pen\tan^{-1}-ol
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