${\mathrm{HNO}}_{3_{ }}+ \mathrm{Ca}{\left(\mathrm{OH}\right)}_2 \to \mathrm{Ca}{\left({\mathrm{NO}}_3\right)}_2+ {\mathrm{H}}_2\mathrm{O}$ is an example of which type of equation?

In the given chemical equation ${\mathrm{HNO}}_{3_{ }}+ \mathrm{Ca}{\left(\mathrm{OH}\right)}_2 \to \mathrm{Ca}{\left({\mathrm{NO}}_3\right)}_2+ {\mathrm{H}}_2\mathrm{O}$, the number of atoms on the reactant side is not equal to the number of atoms on the product side. So, this chemical equation is not balanced. In other words, we can call it an unbalanced chemical equation.