Question

Which of the following reagents could be used to distinguish between propan-2-ol and tert-butyl alcohol?

• A. Lucas reagent
• B. $ZnC{l}_{2}andHCl$
• C. A Cr(VI) reagent like $H_{2}Cr{O}_4$
• D. Bromine water

Answer 1

Answer: (A), (B), (C)

The correct options are
A

Lucas reagent

B

$ZnC{l}_{2}andHCl$

C

A Cr(VI) reagent like $H_{2}Cr{O}_4$

In other words, distinguish between a tertiary alcohol and a secondary alcohol. Using a Chromium VI
compound can oxidize primary alcohols and secondary alcohols and in the process,
the reagent loses its orange colour. The tertiary alcohol does not react with Jones’ reagent.

The Lucas test is positive for the tertiary alcohol very quickly as compared to the secondary alcohol.
The time difference can help identify which is which. The top two options are equivalent.