Answer
IUPAC name for each compound is as follows:
a) 2-phenylethanol
b) 2-methyl-cyclohexanol
c) 1,2-dihydroxybenzene / o-hydroxyphenol
d) 2,3-dicyclohexyl-1-hydroxybenzene.
e) 1-hydroxybenzene / phenol.
Among these compounds, o-hydroxyphenol, 2,3-dicyclohexyl-1-hydroxybenzene and 1-hydroxybenzene are phenols.
Work Step by Step
a) Count the aliphatic C atoms in straight chain. here, it is 2. then the word root is 'eth' and one 'OH' group is present so, the ending name is 'anol'. Now, a Phenyl group is present at C2 position as a substituent. So, '2-phenyl' is added before word root and we get the complete name i.e. 2-phenylethanol.
b) This is a ring compound with a hexagonal ring. So, the no. of C in ring = 6. hence, word root is 'hex' and 'cyclo' prefix is added before 'hex'. Also, there is a OH group present and a methyl substituent attached with the ring. Now, numbering the ring C from 1 to 6 so that OH gets the minimum position i.e. C1 position and methyl gets the C2 position. Now, ending name is 'anol' as there is alcohol group present in the molecule and 2-methyl is added before cyclo. So, the complete name is 2-methylcyclohexanol.
c) two OH groups present in a benzene ring on (1,2) position of the benzene ring. Hence, the name 1,2-dihydroxybenzene.
d) One OH group and two cyclohexane groups are present in benzene ring at 1,2,3 position respectively. So, the name 2,3-cyclohexyl-1-hydroxybenzene.
e) One OH group is present in the benzene ring at C1 position. Hence the name 1-hydroxybenzene
