# What chemical test can differentiate secondary and tertiary alcohols?

I have to perform a chemical test to determine whether the solution is a secondary or a tertiary alcohol. How can I do this? Please explain the procedure and the apparatus.

Or you can try the very simple Lucas' test using zinc chloride and concentrated hydrochloric acid: $$\ce{ROH + HCl -> RCl + H2O}$$

It works best with tertiary alkohols, slow with secondary alcohols and not at all with primary alcohols.

• Add sulfuric acid to a chilled aqueous solution of the alcohol and sodium nitrite.
• Record the UV spectrum.

Tertiary alkyl nitrites show an absorption band at $\lambda$ = 400 nm, secondary and primary alkyl nitrites only below.

A secondary alcohol can be further oxidized to a ketone (reference), while a tertiary alcohol cannot. For example, when you use dichromate as oxidation agent, you will observe a color change of the solution from orange to green. A tertiary alcohol will not react unless your oxidizer is too concentrated.