I'm gonna be giving a 1st year student chemistry tutoring so I'm going over some of his past exam papers to make sure I know all the stuff but I'm already at a question I can't do: http://img571.imageshack.us/img571/5716/26705030.png [Broken] So from the formula, I can see that the degree of unsaturation for the compound is 2. Theres at least one C=C bond in there but the oxygen could either be a carbonyl group or an alcohol. Seeing as it reacts with H2SO4, I assume its an alcohol and the reaction it undergoes is an acid catalysed dehydration of the -OH group. This will yield the alkene. Then ozonolysis breaks the alkene into 2 ketones or aldehydes. Its the final part that has me confused. I don't know what this zinc reduction is and how it could convert ketones or aldehydes into a cyclic ketone.