Question

Which of the following pairs can be distinguished by Lucas test?

पर्याय

• Ethanol and ethylene glycol

• o- and p-cresol

• Propan-1-olandethanol

• Butan-1-ol and 2-methylpropan-2-ol

Answer 1

Butan-1-ol and 2-methylpropan-2-ol

Explanation:

Lucas test is used to distinguish between 1°, 2° and 3° alcohols.

\[\ce{\underset{Butan-1-ol (1° alcohal)}{CH3 - CH2 - CH2 - CH2 - OH} ->[(ZnCl2 - 1HCl)] \underset{(Turbidity appears on heating)}{CH3CH2CH2 - CH2 - Cl}}\]

\[\begin{array}{cc}
\phantom{...}\ce{CH3}\phantom{........................}\ce{CH3}\phantom{}\\
\phantom{}|\phantom{...........................}|\phantom{}\\
\ce{CH3 - C - CH3 ->[(ZnCl2 + HCl)] CH3 - C - CH3}\\
\phantom{}|\phantom{...........................}|\phantom{}\\
\phantom{.....}\ce{\underset{\underset{(3° alcohol)}{2 methyl propan - 2 - ol}}{OH}}\phantom{........}\ce{\underset{(Turbidity appears immediately)}{Cl}}\phantom{}\\
\end{array}\]