# Question #127fe

Mar 15, 2017

The old saying is still true: "There are no stupid questions, …"

#### Explanation:

As you said, the magnesium reacts with the hydrochloric acid to produce magnesium chloride and hydrogen gas.

If you use only a few pieces of $\text{Mg}$ and a lot of $\text{HCl}$, you will have a lot of aqueous $\text{HCl}$ left over with the magnesium chloride dissolved in it.

If you use only a few drops of $\text{HCl}$ and a lot of $\text{Mg}$, you will have a lot of $\text{Mg}$ left over.

If you use just the right amount of each, you will end up with just a solution of magnesium chloride in water.

The balanced equation shows what happens when we have just the right amount of each reactant:

$\underbrace{\text{Mg(s)")_color(red)("magnesium")color(white)(l) + color(white)(l)underbrace("2HCl(aq)")_color(red)("hydrochloric acid") → underbrace("MgCl"_2"(aq)")_color(red)("magnesium chloride") + underbrace("H"_2"(g)")_color(red)("hydrogen}}$

Here is video of an experiment conducted to determine the ratio at which the magnesium and chloride ions will combine. You can see the reaction of Mg and HCl in the video.