- Reaction of an Alcohol with
Conc. HCl: Lucas Test
The mixture of conc. HCl and anhydrous ZnCl2
is called Lucas reagent.
When a tertiary alcohol is treated with Lucas reagent, it instantly
produces turbidity, whereas a secondary alcohol shows turbidity after
5-10 minutes. At room temperature, primary alcohol does not produce
- Oxidation of Alcohols
primary alcohols and secondary alcohols are oxidised
with acidified with K2Cr2O7 solution,
the colour of the dichromate solution changes
from orange to green. With tertiary alcohols, there is no change in colour.
- Saytzeff's Rule
is eliminated from secondary or tertiary alcohol, the alkene formed as the major product is the one where
the H atom
is eliminated from the carbon containing smallest number of H atoms.
- Uses of Alcohols
Ethanol (CH3CH2OH) is used in alcoholic drinks. A
mixture of ethane-1, 2-diol, i.e. glycol (CH2OH - CH2OH),
and water is used in car and lorry radiators. This mixture is commonly
known as antifreeze. Propane-1, 2, 3-triol, i.e. glycerol (CH2OH
- CHOH - CH2OH) is used in medicines and cosmetics. A small
amount of alcohol is added to petrol instead of tetraethyl-lead (IV).
This helps in the smooth burning of petrol.
Phenol is an antiseptic. It should be handled carefully as the crystals
or solution of phenol in water can cause irritation of the skin and may
a hard but brittle material. It is used in electrical fittings such as
plugs and sockets. It is derived from the reaction between phenol with
formaldehyde, catalysed by an acid or alkali.