\((2)\)\(\begin{array}{*{20}{c}} {C{H_3} - CH - Br\,\xrightarrow[{{S_{{N^2}}}}]{{\mathop O\limits^ \ominus H}}} \\ {|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\ {ph\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \end{array}\)\(\begin{array}{*{20}{c}} {ph - CH - OH} \\ {|\,\,\,\,\,\,\,\,} \\ {C{H_3}} \end{array}\)
\((4)\)\(\begin{array}{*{20}{c}} {C{H_3} - CH - Br\,\xrightarrow[{{S_{{N^2}}}}]{{\mathop O\limits^ \ominus H}}} \\ {|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\ {{C_6}{H_{13}\,\,\,\,\,\,}} \end{array}\)\(\begin{array}{*{20}{c}} {C{H_3} - CH - OH} \\ {|\,\,\,\,\,} \\ {\,\,\,\,{C_6}{H_3}} \end{array}\)
As language given, we have to go with option \((1)\) as stereochemistry of chiral centre is not distortet.
પ્રસ્થાન કેન્દ્રાનુરાગી પ્રક્રિયક તરીકે હેલોજેન્સનો ક્રમ હોવો જોઈએ.....