oh ok then take this note terminal alkenes aon treatment with HgSO4/H2SO4 a strong oxidising agent gives rise to formation of C=O group leading to aldehyde formation otherwise it gives a ketone when in the middle sometimes it may even give rise to a ether so here's it the two bond in the second ring of napthalene cleave to give rise to two C=O groups with a -O- linkage forming pthalic anhydride is it ok???