Dehydration : Alcohols undergo dehydration in the presence of dehydrating agents like conc `H_(2)SO_(4),` (or) `H_(3)PO_(4)` etc and form alkenes . The relative ease of dehydration of alcohols follows the following order. Tertiary alcohol `gt` Secondary alcohol `gt` primary alcohol.
`underset(""1^(@) "alcohol")(C_(2)H_(5)OH) underset(443)overset("Conc " H_(2)SO_(4))to CH_(2)=underset("ethene")(Ch_(2))+H_(2)O`
`CH_(3)-underset(2^(@) "alcohol")underset(OH)underset(|)("CH")-CH_(3)underset(440K)overset(85%H_(3)PO_(3))to CH_(3)-underset("Propene")(CH=CH_(2))+H_(2)O`
