Greatest Chemical Reactions

普渡哥

Can we generate and vote the most important chemical reactions in humankind
and modern society?

The first two are:
(1) photosynthesis: CO2 + H20 + hv --> CH2O (carbohydrate) + O2
(2) respiration: CH2O + O2 --> CO2 + H2O + (ATP)

Burning
(3) Coal Combustion: C + O2 --> CO2
(4) Hydrocarbon combustion: CnHm + O2 --> CO2 + H2O

For chemical industries
C + 2H2O --> CO2 + 2H2 or (using methane)
N2 + 3 H2 --> 2 NH3
Making sulfuric acid
Making Cl2 by electrolysis
Oil cracking and reforming