Classification of Alcohols
- Primary alcohols are alcohols in which the carbon atom bonded to the -OH group is attached to one other carbon atom (or alkyl group)
- Secondary alcohols are alcohols in which the carbon atom bonded to the -OH group is attached to two other carbon atoms (or alkyl groups)
- Tertiary alcohols are alcohols in which the carbon atom bonded to the -OH group is attached to three other carbon atoms (or alkyl groups)
Classifying primary, secondary and tertiary alcohols and alcohols with more than one alcohol group
- Only primary and secondary alcohols can get oxidised when mildly oxidised with acidified K2Cr2O7
- Primary alcohols get mildly oxidised to aldehydes
- Secondary alcohols get mildly oxidised to ketones
- Tertiary alcohols do not undergo oxidation with acidified K2Cr2O7
- Therefore, only the oxidation of primary and secondary alcohols will change the colour of K2Cr2O7 solution as the orange Cr2O72- ions are reduced to green Cr3+ ions
Only primary and secondary alcohols can be oxidised, turning the orange solution greenNo colour change is observed with a tertiary alcohol
