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1. Which preposition should be after 'obtained'?

2. Is 'hydrogen sulfide' spelled correctly? Isn't it BE 'sulphide'?

3. Which is better 'unfavourable' or 'adverse' or neither?

Thank you very much for your patience and effort.

Liquid gass obtained on/? the atmospheric distillation apparatus or cracking processes contains sulphur compounds (hydrogen sulfide/sulphide and merkaptans), which cause corrosion and very unpleasant odour, which has an unfavourable/adverse effect on the application of liquid gas.
Comments  
sulfide/sulphide - depends whether you're American or British.
Corrected version :

Liquid gas obtained from atmospheric distillation apparatus or cracking processes contains sulphur compounds (hydrogen sulphide and mercaptans), which cause corrosion and very unpleasant odours, which have a detrimental effect on the application of liquid gas.
Thank you Alan. Is here mercaptane plural?
Students: Are you brave enough to let our tutors analyse your pronunciation?
yes, mercaptans is correct.
Thank you Alan.