Heating an aqueous solution of a salt of this anion and sulfuric acid is used to measure the “[this anion] index” of water quality. The Kappa number of pulp is determined by measuring the consumption of a salt with this anion. A salt of this anion and osmium tetroxide are commonly used in the syn dihydroxylation of alkenes. Heating alkylbenzenes with an aqueous solution of a salt with this anion produces benzoates. A solution with this anion changes to a (*) brown color to show the presence of an unsaturated carbon-carbon (-5[1])double bond in Baeyer’s test. Due to the +7 oxidation state of its central atom, this anion is a strong oxidizing agent when bonded to (10[2])potassium. For 10 points, purple (-5[1])solutions are produced by what polyatomic anion composed of four oxygens around a manganese atom? (0[2])■END■