Multiple choice How many peroxide linkages are present in S2O8-2? 1 2 3 5 Reveal answer Fill a bubble to check yourself A Correct answer Explanation This option is correct because , S2O8-2, is a dimerize form of SO4-2 in which one O - atom of each sulphate ion link together to form dimer and that linkage is peroxide linkage and only one linkage is persent in this ion.