Answer
a) pentanol
2-methyl-2,4-pentanediol
b) trans-1,2-cyclohexanediol
4-methyl-3-pentenol.
Work Step by Step
a) Look at the first compound. No. of C in straight chain = 5. hence, root name is 'pent' and ending name is 'anol' for OH group present in that compound and OH group is present at C1 position. so, the complete name is pentanol.
The second compound: No. of C in straight chain = 5. hence, root name is 'pent' and two OH group present here. Numbering of C atom is done so that the C atoms associated with OH group gets minimum position. So, Numbering is done from left to right. so, 2,4-pentanediol. Now, we see that one methyl is present at C2 position so, 2-methyl is added before root name and we get the complete name.
b) two same group on two ring C are on opposite direction i.e. trans isomer. No. of C in ring = 6. hence, root name is 'cyclohexane' and two OH group present at C1 and C2 position. Hence, 1,2-cyclohexanediol.
