Question

(B) (b) Give a simple chemical test to distinguish between butan-1-ol and butan-2-ol.

Hint:

The oxidation test and iodoform test can help distinguish between primary and secondary alcohols. Primary alcohols are oxidized to carboxylic acids, while secondary alcohols form ketones.

Answer 1

A straightforward chemical test to differentiate between butan-1-ol and butan-2-ol is the oxidation test using potassium dichromate (\( K_2Cr_2O_7 \)) in an acidic medium. Butan-1-ol will be oxidized to butanoic acid, while butan-2-ol will be oxidized to acetone.
Butan-1-ol: Upon oxidation, it forms a carboxylic acid, butanoic acid.
Butan-2-ol: Upon oxidation, it forms a ketone, acetone.
Another test involves the reaction with iodine and NaOH:
Butan-1-ol forms a yellow precipitate of iodoform when treated with iodine and NaOH.
Butan-2-ol also forms a yellow precipitate of iodoform, but the intensity of the reaction can be used for differentiation.
\bigskip