Question

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

Answer 1

This reaction is a displacement reaction.

Step-by-step 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,

• 
  `\rm Mg`
  `\rm` is an element. Magnesium is the only type of atom that it contains.
• 
  `\rm H_2` is also an element. Hydrogen is the only type of atom that it contains (Even though there are two hydrogen atoms in each
• 
  `\rm MgCl_2` is a compound. It contains both magnesium atoms and chlorine atoms.

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

• 
  `\rm Mg` (an element) reacts with
  `\rm HCl` (a compound)
• to produce
  `\rm H_2` (another element) and
  `\rm MgCl_2` (another compound).

Hence this reaction is a displacement reaction.

As a side note, this reaction matches the pattern:

`\rm \underbrace{\rm \text{Reactive Metal}\; (s)}_{\text{element}} + \underbrace{\rm \text{Acid}\; (aq)}_{\text{compound}} \to \underbrace{\rm \text{Salt}\; (aq)}_{\text{another}\atop\text{compound}} + \underbrace{\rm \rm H_2\; (g)}_{\text{another}\atop\text{element}}`.

In other words, if the
`\rm Mg\; (s)` here is replaced with a different metal that is sufficiently reactive (such as aluminum
`\rm Al\; (s)`,) the reaction should still be a displacement reaction.