What would hydrochloric acid do if it came in contact with a metal such as magnesium?

Answer 1

Now the thing is :

Hydrochloric acid HCl , has covalent bonding (ie. electrons are shared) but still H and Cl has partial charges because Cl is highly electronegative.

When HCl is in gaseous state the H-Cl bond is very strong and magnesium is unable to react with it. But when it is in water ( water H2O ; O is highly electronegative so H has partial +ve charge O has partial -ve charge H of H2O Surround the Cl of HCl and break it in H+ and Cl-)

Now what happens is :

Mg gives 2 electrons 2H+ takes them forms 2H and combine to form H2 gas

Mg is now of the form Mg2+ Which combines with 2Cl- and form MgCl2