In this I/GCSE Chemistry blog post, we will be looking into how the contact process works, let's go!

The manufacture of sulfuric acid

1. First, sulfur dioxide is made, mostly by burning sulfur in air.
2. Sulfur trioxide is then made by reacting sulfur dioxide with oxygen. 
3. The two gases react together in contact with a solid catalyst, vanadium(V) oxide. 
4. It is a reversible reaction, and so the yield of sulfur trioxide is affected by temperature and pressure. 
5. Once again, the forward reaction is exothermic, so 450˚C is used as a compromise temperature. 
6. Despite the fact that a higher pressure would increase yield, a pressure of only 2 atmospheres is used because the yield is already 98% so higher pressures would not be economical.

1. The sulfur trioxide is then absorbed into concentrated sulfuric acid to make oleum (H2

_S2_O7₎. This is then carefully diluted to make a concentrated solution of sulfuric acid.

Sulfuric acid is used in the manufacture of detergents, fertilisers, and paints.

That is all!

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References:

https://www.google.com/url?sa=i&url=http%3A%2F%2Fwww.dynamicscience.com.au%2Ftester%2Fsolutions1%2Fchemistry%2Fsulfuricacid.html&psig=AOvVaw2cV3m97hIhuAuv3FtOQrdH&ust=1629638247874000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCLDK5dmZwvICFQAAAAAdAAAAABAD

https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.toppr.com%2Fask%2Fcontent%2Fstory%2Famp%2Fsulphuric-acid-preparation-and-physical-properties-53103%2F&psig=AOvVaw2o0o7Exy0wypeXK2PQ8JpR&ust=1629638925290000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCNCRzpycwvICFQAAAAAdAAAAABAI

https://www.google.com/url?sa=i&url=https%3A%2F%2Fpubchem.ncbi.nlm.nih.gov%2Fcompound%2FOleum&psig=AOvVaw3TyoLPglvji91Akmn_zruc&ust=1629639043594000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCNDVs9WcwvICFQAAAAAdAAAAABAD