Question -
Answer -
Manufacture of sulphuric acid byContact process involves three steps.
1. Burningof ores to form SO2
2. Conversionof SO2 to SO3 by the reaction of the formerwith O2
(V2O5 isused in this process as a catalyst.)
3. Absorptionof SO3 in H2SO4 to give oleum (H2S2O7)
Thekey step in this process is the second step. In this step, two moles of gaseousreactants combine to give one mole of gaseous product. Also, this reaction isexothermic. Thus, in accordance with Le Chatelier’s principle, to obtain themaximum amount of SO3 gas, temperature should be low andpressure should be high.