Question

The student wanted to find out what would happen when acids are

added to other substances such as metals. In an experiment, they
added magnesium to hydrochloric acid. The full, balanced equation is
provided below.
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
a) Provide an ionic and net ionic equation for this reaction between
magnesium and hydrochloric acid (also showing the cancelling
out of like species).
b) Briefly describe what the student would observe happening
during the reaction.
c) Name the salt formed by this reaction.
The student reacted another metal, calcium with hydrochloric acid.
d) Provide a full balanced equation (to include state symbols) and a
net ionic equation for this reaction.
e) The student noted that the same observations were seen in this
reaction. Provide a general word equation to show what
happens when a metal reacts with an acid.

Answer 1

a) The ionic equation for the reaction between magnesium and hydrochloric acid is Mg(s) + 2H+(aq) + 2Cl-(aq) → Mg2+(aq) + 2Cl-(aq) + H2(g). The net ionic equation for this reaction is Mg(s) + 2H+(aq) → Mg2+(aq) + H2(g). In this ionic equation, the species that cancel out are the Cl- ions, which appear on both the reactant and product sides of the equation.

b) During the reaction between magnesium and hydrochloric acid, the student would observe bubbles of hydrogen gas forming as the magnesium reacts with the hydrochloric acid. The student may also observe the magnesium ribbon or strip turning a dull gray color as it reacts with the hydrochloric acid.

c) The salt formed by this reaction is magnesium chloride.

d) The full balanced equation for the reaction between calcium and hydrochloric acid is Ca(s) + 2HCl(aq) → CaCl2(aq) + H2(g). The net ionic equation for this reaction is Ca(s) + 2H+(aq) → Ca2+(aq) + H2(g).

e) When a metal reacts with an acid, a salt and hydrogen gas are produced. The general word equation for this type of reaction is metal + acid → salt + hydrogen gas.