The structural formula of cyclohexanol is ____.

The order of reactivity of the following alcohols towards $\mathrm{HCl}$ is ______.
($i$)   $$\begin{gathered} \text{OH} \\ {\text{F-CH}}_{\text{2}}\text{-}\stackrel{|}{\text{C}}{\text{H-CH}}_{\text{3}} \end{gathered}$$

($ii$) $$\begin{gathered} \text{ OH} \\ {\text{F-CH}}_{\text{2}}{\text{-CH}}_{\text{2}}\text{-}\stackrel{|}{\text{C}}{\text{H-CH}}_{\text{3}} \end{gathered}$$

($iii$)  $$\begin{gathered} \text{ OH} \\ {\text{H}}_{\text{3}}\text{C-}\stackrel{|}{\text{C}}{\text{H-CH}}_{\text{3}} \end{gathered}$$

($iv$) ${\text{H}}_{\text{5}}{\text{C}}_{\text{6}}{\text{-CH}}_{\text{2}}\text{OH}$