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Acids and Alkalis

Manufacture of Sulfuric Acid  -  The Contact Process.

The Effect of Pressure on the Formation of Sulfur Trioxide.

The formation of sulfur trioxide is reversible.

sulfur dioxide    +   oxygen          sulfur trioxide
2SO_2(g)       +    O_2(g)                2SO_3(g)

Increasing the pressure will increase the rate of the reaction
and increase the amount of sulfur trioxide in the equilibrium mixture.

A high pressure will give the best yield of sulfur trioxide.

The reaction is run at between 1 and 2 atmospheres
which gives 99% conversion of sulfur dioxide to sulfur trioxide.

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