$(a)$ $\begin{array}{*{20}{c}}
{C{H_3} - CH - Br} \\
{|\,} \\
{\,\,\,\,\,\,{C_2}{H_5}}
\end{array}$
$(b)$ $\begin{array}{*{20}{c}}
{\begin{array}{*{20}{c}}
{\,\,Br} \\
|
\end{array}} \\
{C{H_3} - C - C{H_3}} \\
| \\
{\,\,\,\,\,\,\,\,\,{C_2}{H_5}}
\end{array}$
$(c)$ $\begin{array}{*{20}{c}}
{C{H_3}{\mkern 1mu} - CH{\mkern 1mu} - {\mkern 1mu} {\mkern 1mu} C{H_2}Br} \\
{|\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{{C_2}{H_5}\,\,\,}
\end{array}$
$(1)$ $CH_3CH_2-CH_2-OH$
$(2)$ $\begin{array}{*{20}{c}}
{C{H_3} - C{H_2} - CH - OH} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|\,\,\,\,} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,C{H_3}}
\end{array}$
$(3)$ $\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,\,\,\,\,C{H_3}} \\
\,\,\,\,\,\,|
\end{array}} \\
{C{H_3} - C{H_2} - C - OH} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,C{H_3}}
\end{array}$