The second reaction in the formation of sulfuric acid occurs slowly. no2 is added to the reaction to speed it up. in which form would this substance be a homogeneous catalyst for this reaction? no2(g) no2(l) no2(s) no2(aq)

NO2 (g)

If the catalyst and the reactants are in same phase, the catalysis is called homogeneous catalysis and the catalyst is called a homogeneous catalyst.

H2SO4 is usually synthesized by Contact process

The 1st step of contact process involves the reaction of sulfur and oxygen to produce sulfur dioxide.

In 2nd step sulfur dioxide is converted into sulfur trioxide by reacting it with O2 in the presence vanadium pentaoxide. We can see that both the reactants are in gaseous form so we use N02 in gaseous form.