ROH + HX  ®  R–X + H2O
The difference in reactivity of three classes of alcohols with HCl
distinguishes them from one another (Lucas test) Alcohols are soluble
in Lucas reagent (conc HCl and ZnCl2) while their halides are immiscible
and produce turbidity in solution In case of tertiary alcohols, turbidity
is produced immediately as they form the halides easily