Question

Lucas test is done for:

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

Answer 1

Answer: (B)

alcohols

Answer 2

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 $ZnCl_2$ (Lucas reagent). $R- OH + HCl \xrightarrow{ ZnCl _{2}} R Cl + H _{2} O$ * 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.