Question

Lucas test is done for:

• A. alkyl halides
• B. alcohols
• C. acids
• D. aldehydes

Answer 1

Answer: (B)

Lucas test is used to distinguish between primary, secondary and tertiary alcohol. This test is based upon relative reactivites of various alcohols towards conc. $HCl$ in presence of $ZnC{l}_2$ (Lucas reagent).
$R-OH+HCl\stackrel{ZnC{l}_2}{\to }RCl+H_{2}O$
* If cloudiness appears immediately, tertiary alcohol is indicated.
* If cloudiness appears within five minutes, secondary alcohol is indicated.
* If cloudiness appears only upon heating primary alcohol is indicated.
Besides this Victor Meyer test is also used to differentiate between $p,s$ and $t$ alcohol.