The combustion of hydrogen-oxygen mixture is used to produce very high temperatures (=2500∘ C) needed for certain types of welding operations.
H2(g)+12O2(g)→H2O(g); ΔH=−230.9 kJ
Quantity of heat, (in kJ) evolved when a 200 g mixture containing equal parts of H2 and O2 mass is burned, is