A compound where the hydroxy group is bonded to a sp2-hybridised carbon-carbon double bond (C=C) is called vinylic alcohol. They contains vinyl group i.e. H−C=CH2.A compound where the hydroxy group is bonded to a sp2-hybridised carbon-carbon double bond (C=C) is called vinylic alcohol. They contains vinyl group i.e. H−C=CH2. Thus, but-2-en-2-ol