Chemistry ALCOHOLS : IDENTIFICATION OF PRIMARY, SECONDARY AND TERTIARY ALCOHOLS
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ALCOHOLS : IDENTIFICATION OF PRIMARY, SECONDARY AND TERTIARY ALCOHOLS

Lucas Test :

`text(Alcohols) + ZnCl_2 + HCl`

i) Alcohol : `RCH_2OH underset(HCl)overset(ZnCl_2)->` No reaction at room tempreture

ii) Alcohol : `R_2CHOH underset(HCl)overset(ZnCl_2)-> R_2CH - Cl` White turbidity after `5`-`10` min.

iii) Alcohol : `R_3C- OH underset(text(or) HI)overset(ZnCl_2)-> R_3C - Cl` white turbidity instaneously

Dichromate Test (Oxidation Test) :

This test is based on the fact that three types of monohydric alcohols give different oxidation products on oxidation.

The unknown alcohol is treated with sodium dichromate in dilute sulphuric acid (orange solution) at room temperature. Then the oxidation products are identified.

(i) A carboxylic acid with same number of carbon atoms as in the alcohol, if formed confirms the primary alcohol. The colour of the solution changes from orange to green.

(ii) A ketone with same number of carbon atoms as in the alcohol if formed confirms the secondary alcohol. The colour of the solution also changes from orange to green.

(iii) In case the colour of the solution does not change, i.e. it remains same, then it is `3^o` alcohol.

Victor Meyer Test :

`1^o` alcohol : See fig.1.

Nitrolic acid on treatment with alkali gives colouration

`2^o` alcohol : See fig.2.

`3^o` alcohol : See fig.3.
 
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