[Pt(NH3)2Cl2] + 2NaOH + 2H2O → Pt(OH)2 + 2(NH3•H2O) + 2NaCl
Trans(cis)-dichloridodiammineplatinum react with sodium hydroxide and water to produce platinum(II) hydroxide, ammonium hydroxide and sodium chloride. Sodium hydroxide - concentrated, cold solution.