A piece of magnesium is put in a test tube containing hydrochloric acid. Explain the chemical reaction.

The magnesium reacts with the acid, producing visible bubbles of hydrogen gas. (Optional) If the flame of a butane fireplace lighter is held above the bursting bubbles, they will produce audible pops as the hydrogen ignites. Magnesium ribbon is a flammable solid. Hydrochloric acid is a corrosive liquid.

Explanation:

Magnesium reacts with hydrochloric acid according to the equation: Mg(s) + 2 HCl(aq) --> MgCl2(aq) + H2(g) This demonstration can be used to illustrate the characteristic reaction of metals with acid, a single replacement reaction, or to demonstrate the generation of hydrogen gas.

if you mean hydrogen and oxygen then water is the product