Consider the following reaction,
the product Z is:
CH3CH2 - O - CH2 - CH3
CH3 - CH2 - O - SO3H
CH3CH2OH
CH2 = CH2
PBr3 act as a halogenating agent that converts -OH group into -Br. Then Alc. KOH is a dehydrohalogenation agent. H2S04 and H20 converts an olefin into alcohol.