[Pd(NH3)4]Cl2 + 2HCl → [Pd(NH3)2Cl2] + 2NH4Cl
Tetraamminepalladium(II) chloride react with hydrogen chloride to produce trance-dichloridodiamminepalladium(II) and ammonium chloride. Hydrogen chloride - concentrated solution. This reaction takes place at a temperature near 0°C.