Identify Major Product P in Multistep Organic Reaction Sequence

To determine the major product $P$ in the given reaction sequence, we can break down the process into individual chemical steps:

Step 1 & 2: Hydrolysis of Propanenitrile

The starting material is propanenitrile ($\text{CH}_3\text{CH}_2\text{C}\equiv\text{N}$).

• (i) Reaction with $\text{OH}^-/\text{H}_2\text{O}$ and heat ($\Delta$) causes alkaline hydrolysis of the nitrile group ($-\text{C}\equiv\text{N}$) to form propanoate ion ($\text{CH}_3\text{CH}_2\text{COO}^-$).
• (ii) Acidification with $\text{H}_3\text{O}^+$ protonates the carboxylate ion to yield propanoic acid ($\text{CH}_3\text{CH}_2\text{COOH}$).

$\text{CH}_3\text{CH}_2\text{C}\equiv\text{N} \xrightarrow[\Delta]{(i)\ \text{OH}^-/\text{H}_2\text{O}} \text{CH}_3\text{CH}_2\text{COO}^- \xrightarrow{(ii)\ \text{H}_3\text{O}^+} \text{CH}_3\text{CH}_2\text{COOH}$

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Step 3 & 4: Hell-Volhard-Zelinsky (HVZ) Reaction

• (iii) & (iv) Propanoic acid ($\text{CH}_3\text{CH}_2\text{COOH}$) is reacted with $\text{Cl}_2$ in the presence of red phosphorus ($\text{Red P}$), followed by treatment with $\text{H}_2\text{O}$.
• This is the Hell-Volhard-Zelinsky (HVZ) reaction, which selectively substitutes an $\alpha$-hydrogen atom of carboxylic acids with a halogen atom ($\text{Cl}$).

$\text{CH}_3\text{CH}_2\text{COOH} \xrightarrow{(iii)\ \text{Cl}_2/\text{Red P}} \text{CH}_3\text{CH(Cl)}\text{COCl} \xrightarrow{(iv)\ \text{H}_2\text{O}} \text{CH}_3\text{CH(Cl)}\text{COOH}$

The final major product $P$ is 2-Chloropropanoic acid.

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Conclusion:

The correct IUPAC name of the major product $P$ is 2-Chloropropanoic acid, which corresponds to Option A.