Question

Which alcohol produces turbidity with Lucas reagent most slowly?

Answer 1

Lucas test

• Lucas test is used to differentiate primary, secondary and tertiary alcohol. The reaction that occurs in the Lucas test can be seen as a nucleophilic substitution reaction.
• $\mathrm{HCl}$ in the presence of anhydrous zinc chloride to form chloroalkanes.
• The alcohols are soluble in the Lucas reagent whereas the resulting chloroalkanes are not soluble. Thus, the formation of chloroalkanes is indicated by the appearance of cloudiness.
• Tertiary alcohols give an immediate appearance of turbidity.
• Appearances of cloudiness after a few minutes in case of secondary alcohols.
• Primary alcohols do not give turbidity.

Hence secondary alcohol produces turbidity with Lucas reagent most slowly.