i dont get why we use excess air when converting SO2 to SO3 in the contact process......i know it shifts the equilibirium shifts to the right but i dont get why...??????
According to the Le Chateilier's (dunno how to spell it ), so according to the principle if any change in the factors which affect the equilibrium is altered than the reaction behaves in a way which opposes the change and tries to attain eq. Sooo if you add excess O2 the concentration of the reactants increases and so the equilibrium shifts to the right to produce more products so they reaction will come to eq. again, hence increasing the conc. of the products so SO3 increases!