The reaction of zinc with dilute and concentrated nitric acid, respectively, produces:

With dilute solution of nitric acid, Zn produces ${\mathrm{N}}_2\mathrm{O}$: $4\mathrm{Zn}+10{\mathrm{HNO}}_3\to 4\mathrm{Zn}{\left({\mathrm{NO}}_3\right)}_2+{\mathrm{N}}_2\mathrm{O}+5{\mathrm{H}}_2\mathrm{O}$

With concentrated nitric acid, ${\mathrm{NO}}_2$ is produced. $\mathrm{Zn}+4{\mathrm{HNO}}_3\to \mathrm{Zn}{\left({\mathrm{NO}}_3\right)}_2+2{\mathrm{NO}}_2+2{\mathrm{H}}_2\mathrm{O}$