Which of the following is produced when magnesium (Mg) combusts? A. CO2

B. MgO

C. O2

D. H2O

MgO is produced when magnesium is undergo combustion

that is 2 Mg + O2 = 2MgO

2 mole of magnesium (Mg) during combustion reaction react with 1 mole of oxygen (O2) to form 2 moles of magnesium oxide (MgO). a combustion reaction is a reaction by which a substance react with oxygen and it is always exothermic (releases heat energy)