What type of chemical reaction is represented by Mg(s) + 2HCI(aq) MgCl2(aq) + H2(g)

This reaction is a displacement reaction.

Explanation:

Both elements and compounds are chemical substances. However, there's only one type of atom in an element. In a compound, there are at least two different kinds of atoms.

For example,

In a displacement reaction, an element reacts with a compound to produce another element and a different compound. In this reaction,

Hence this reaction is a displacement reaction.

As a side note, this reaction matches the pattern:

.

In other words, if the here is replaced with a different metal that is sufficiently reactive (such as aluminum ,) the reaction should still be a displacement reaction.