H2SO4 to SO3 in the desert

Question

If we have a H2SO4 barrel in the desert, how is it possible to find SO3 on the sand near it. knowing that there is no way for the H2SO4 to reach its boiling point which is 340°C. is there any possible reaction instead of the thermal decomposition?

Answer 1

The H₂SO₄ doesn't have to boil to generate SO₃, only the water in the H₂SO₄ needs to be removed, and this could certainly happen at desert temperatures.  Removal of H₂O from H₂SO₄ will result in the formation of SO₃.