As the complex gives two moles of AgCl ppt. with AgNO3 solution, so the complex must have two ionisable Cl atoms. Hence the probable complex, which gives three mole ions may be [Co(NH3)5‌NO2]Cl2. [Co(NH3)5(NO2)]Cl2→[Co(NH3)5(NO2)]2++2Cl− one mole →3 mole ions.