18. The reverse reaction of sulfur dioxide and oxygen forming sulfur trioxide would be the decomposition of sulfur trioxide to sulfur dioxide and oxygen.
That is incorrect. The reverse reaction of sulfur dioxide and oxygen forming sulfur trioxide (SO2 + O2 -> 2SO3) would be the combination of sulfur dioxide and oxygen to produce sulfur trioxide. The decomposition reaction of sulfur trioxide would result in the formation of sulfur dioxide and oxygen.
