<Dl> <Dd> 4V + O → 4V + 2O </Dd> </Dl> <Dd> 4V + O → 4V + 2O </Dd> <P> Hot sulfur trioxide passes through the heat exchanger and is dissolved in concentrated H SO in the absorption tower to form oleum: </P> <Dl> <Dd> H SO (l) + SO (g) → H S O (l) </Dd> </Dl>

Advantages of contact process for manufacture of sulphuric acid