Thermo chemical reactions are chemical reactions that involve changes in temperature. Examples of these reactions include combustion, oxidation, and neutralization.
Thermo-chemical reactions involving HCl and magnesium involve the formation of magnesium chloride (MgCl2) from the combination of the two compounds. The reaction is represented as follows:
Mg + 2HCl → MgCl2 + H2
The reaction is exothermic, releasing heat energy.