[Co(H2O)2(NH3)4]2(SO4)3 + 6HCl → 2[Co(NH3)4Cl2]Cl + 3H2SO4 + 4H2O
Trance-tetraamminediaquacobalt(III) sulphate react with hydrogen chloride to produce chloride trance-dichloridotetraamminecobalt(III) sulfuric acid and water. Hydrogen chloride - concentrated solution. This reaction takes place at a temperature near 0°C.