What is aquaregia ? Write its equation with gold & Platinum.

Aquaregia is a mixture of Conc. HCl and Conc. HNO₃ in 3 :1 ratio. It is used for dissolving noble metals like gold and Platinum
$\mathrm{Au}+4{\mathrm{H}}^{+}+{\mathrm{NO}}_3^{-}+4{\mathrm{Cl}}^{-}\stackrel{ }{\to }{\mathrm{AuCl}}_4^{-}+\mathrm{NO}+2{\mathrm{H}}_2\mathrm{O}$
$3\mathrm{Pt}+16{\mathrm{H}}^{+}+4{\mathrm{NO}}_3^{-}+18{\mathrm{Cl}}^{-}\stackrel{ }{\to }3{\mathrm{PtCl}}_6^{-2}+4\mathrm{NO}+8{\mathrm{H}}_2\mathrm{O}$