Acid and Metal Oxide

Acid and metal oxide

When an acid reacts with a metal oxide a salt and water are also formed. Some examples are:

• \(2\text{HCl (aq)} + \text{Na}_{2}\text{O (aq)} \rightarrow \text{H}_{2}\text{O (l)} + 2\text{NaCl}\)
• \(2\text{HBr (aq)} + \text{MgO} \rightarrow \text{H}_{2}\text{O (l)} + \text{MgBr}_{2}\text{(aq)}\)
• \(6\text{HCl (aq)} + \text{Al}_{2}\text{O}_{3} \text{(aq)} \rightarrow 3\text{H}_{2}\text{O (l)} + 2\text{AlCl}_{3}\text{(aq)}\)

We can write a general equation for the reaction of a metal oxide with an acid: \[2y\text{H}^{+}\text{(aq)} + \text{M}_{x}\text{O}_{y}\text{(aq)} \rightarrow y\text{H}_{2}\text{O (l)} + x\text{M}^{n+}\text{(aq)}\] Where \(n\) is the group number of the metal. The \(x\) and \(y\) represent the ratio in which the metal combines with the oxide and depends on the valency of the metal.