Initial Compound is like this Ph---CO---O----CO----CH3.(Ph means phenyl) It is reacted with H3O+. What will be product? I think first attack will be at carbonyl carbon near methyl. Because phenyl ring will donate electrons to carbonyl group near it and make it less attractive towards hydroxide. Now change the compound. Ph---CO---O----CO----CH2-----CH3.(Ph means phenyl) add methyl at meta position in phenyl (with respect to carbonyl group attached to benzene ring). What will happen when this will reacted with water. I think same kind of thing as it happen in last case. Non phenyl carbonyl group will be attacked. Am i correct in both cases?? if not then please point out the mistake. thanks!