Question

In a laboratory investigation, magnesium reacts with hydrochloric acid to produce hydrogen gas and magnesium chloride. This reaction is represented by the unbalanced equation below.
Mg(s) + HCl(aq) ==>H2(g) + MgCl2(aq)

State, in terms of the relative activity of elements, why this reaction is spontaneous.

Answer 1

According to the reactivity series of metals, Mg is more reactive than H. Therefore, this reaction is spontaneous.
Hope this helps~

Answer 2

Because Mg stands before H on the metal reactivity scale