Question

How does 1.0 M HCl and 1.0 M HC2H3O2 react differently with Mg? Which one reacts more vigorously?

Answer 1

The reaction between HCl and Mg is

2 HCl (aq) + Mg(s) --------------> MgCl2 (aq) + H2(g)

and the reaction between HC2H3O2 and Mg is also similar

2HC2H3O2 + Mg ------------------> Mg(C2H3O2)2 + H2 (g)

Though the reaction is similar to form the similar salt and H2 gas

the reaction with 1.0M Hcl(a strong acid) is much faster than with acetic acid aweak acid.

It is due to the faact that in HCl the ionization is almost complete, thus has more H+ ions to react while in HCH3O2 which is a weak acid, the dissociation is less thus the [H=] is less thus the reaction is much slower.