Correct the following statements-
Aqua regia contains one part by volume of nitric acid and three parts by volume of hydrochloric acid.

1. Aqua regia is a mixture of three moles of concentrated hydrochloric acid $\left(\mathrm{HCl}\right)$ and one mole of concentrated nitric acid ${\mathrm{HNO}}_3$ i.e. $3:1$ ratio of $\mathrm{HCl}$ and ${\mathrm{HNO}}_3$ it is used to dissolve metals such as gold Mercury and many more.
2. Reaction- $\underset{\mathrm{Cons}}{3\mathrm{HCl}}+\underset{\mathrm{cons}}{{\mathrm{HNO}}_3}\to \underset{\mathrm{Tilder}\mathrm{reagent}}{\mathrm{NOCl}}+\underset{\mathrm{Nascant}\mathrm{Chloride}}{\left[\mathrm{Cl}\right]}+{\mathrm{H}}_2\mathrm{O}$
3. So, the correct statement is Aqua regia contains one part by volume of concentrated nitric acid and three parts by volume of concentrated hydrochloric acid.