$(I) \;CH_2 = CH - OH $
$(II)\; CH_2 = CH - CH_2OH$
$(III)\;CH_3 - CH_2 - OH$
$(IV)\; \begin{matrix} C{{H}_{3}}-CH-C{{H}_{3}} \\ |\,\,\,\, \\ OH \\ \end{matrix}$
$CH _{2}=C H-\stackrel{\oplus}C H_{2}>C H_{3}-\stackrel{\oplus}C H-C H_{3}>$ $C H_{3}-\stackrel{\oplus}C H_{2}>C H_{2}=\stackrel{\oplus}C H$